|
| 620.105 | Purpose |
| 620.110 | Definitions |
| 620.115 | Prohibition |
| 620.125 | Incorporations by Reference |
| 620.130 | Exemption from General Use Standards and Public and Food Processing Water Supply Standards |
| 620.135 | Exclusion for Underground Waters in Certain Man-Made Conduits |
| SUBPART B: GROUNDWATER CLASSIFICATION | |
| Section | |
| 620.201 | Groundwater Designations |
| 620.210 | Class I: Potable Resource Groundwater |
| 620.220 | Class II: General Resource Groundwater |
| 620.230 | Class III: Special Resource Groundwater |
| 620.240 | Class IV: Other Groundwater |
| 620.250 | Groundwater Management Zone |
| 620.260 | Reclassification of Groundwater by Adjusted Standard |
| SUBPART C: NONDEGRADATION PROVISIONS | |
| FOR APPROPRIATE GROUNDWATERS | |
| Section | |
| 620.301 | General Prohibition Against Use Impairment of Resource Groundwater |
| 620.302 | Applicability of Preventive Notification and Preventive Response Activities |
| 620.305 | Preventive Notification Procedures |
| 620.310 | Preventive Response Activities |
| SUBPART D: GROUNDWATER QUALITY STANDARDS | |
| Section | |
| 620.401 | Applicability |
| 620.405 | General Prohibitions Against Violations of Groundwater Quality Standards |
| 620.410 | Groundwater Quality Standards for Class I: Potable Resource Groundwater |
| 620.420 | Groundwater Quality Standards for Class II: General Resource Groundwater |
| 620.430 | Groundwater Quality Standards for Class III: Special Resource Groundwater |
| 620.440 | Groundwater Quality Standards for Class IV: Other Groundwater |
| 620.450 | Alternative Groundwater Quality Standards |
| SUBPART E: GROUNDWATER MONITORING AND ANALYTICAL PROCEDURES | |
| Section | |
| 620.505 | Compliance Determination |
| 620.510 | Monitoring and Analytical Requirements |
| SUBPART F: HEALTH ADVISORIES | |
| Section | |
| 620.601 | Purpose of a Health Advisory |
| 620.605 | Issuance of a Health Advisory |
| 620.610 | Publishing Health Advisories |
| 620.615 | Additional Health Advice for Mixtures of Similar-Acting Substances |
| 620.APPENDIX A | Procedures for Determining Human Toxicant Advisory Concentrations for Class I: Potable Resource Groundwater |
| 620.APPENDIX B | Procedures for Determining Hazard Indices for Class I: Potable Resource Groundwater for Mixtures of Similar-Acting Substances |
| 620.APPENDIX C | Guidelines for Determining When Dose Addition of Similar-Acting Substances in Class I: Potable Resource Groundwaters is Appropriate |
| 620.APPENDIX D | Information Required for Groundwater Management Zone Application under 35 Ill. Adm. Code 620.250(b) and Corrective Action Completion Certification under 35 Ill. Adm. Code 620.250(d) |
| 620.APPENDIX E | Similar-Acting Substances |
| 620.TABLE A Similar-Acting Noncarcinogenic Constituents | |
| 620.TABLE B Similar-Acting Carcinogenic Constituents |
| "Act" means the Environmental Protection Act [415 ILCS 5]. | |
| "Agency" means the Illinois Environmental Protection Agency. | |
| "Aquifer" means saturated (with groundwater) soils and geologic materials that are sufficiently permeable to readily yield economically useful quantities of water to wells, springs, or streams under ordinary hydraulic gradients. [415 ILCS 55/3(b)] | |
| "BETX" means the sum of the concentrations of benzene, ethylbenzene, toluene, and xylenes. | |
| "Board" means the Illinois Pollution Control Board. | |
| "Carcinogen" means a contaminant that is classified as a Category A1 or A2 Carcinogen by the American Conference of Governmental Industrial Hygienists; or a Category 1 or 2A/2B carcinogen by the World Health Organization's International Agency for Research on Cancer; or a "Human carcinogen" or "Anticipated Human Carcinogen" by the United States Department of Health and Human Service National Toxicological Program; or a Category A or B1/B2 Carcinogen or as "carcinogenic to humans" or "likely to become carcinogenic to humans" by the United States Environmental Protection Agency in Integrated Risk Information System or a Final Rule issued in a Federal Register notice by the USEPA. [415 ILCS 5/58.2] | |
| "Community water supply" means a public supply that serves or is intended to serve at least 15 service connections used by residents or regularly serves at least 25 residents. [415 ILCS 5/3.145] | |
| "Contaminant" means any solid, liquid, or gaseous matter, any odor, or any form of energy, from whatever source. [415 ILCS 5/3.165] | |
| "Corrective action process" means the procedures and practices that a regulatory agency may perform, require, or otherwise oversee, including corrective action and controls and management, to address a potential or existing violation of any Subpart D standard due to a release of one or more contaminants. |
| "Cumulative impact area" means the area, including the coal mine area permitted under the Surface Coal Mining Land Conservation and Reclamation Act [225 ILCS 720] and 62 Ill. Adm. Code 1700 through 1850, within which impacts resulting from the proposed operation may interact with the impacts of all anticipated mining on surface water and groundwater systems. | |
| "Detection" means the identification of a contaminant in a sample at a value equal to or greater than the: | |
| "Method detection limit" or "MDL"; or | |
| "Lower limit of quantitation" or "LLOQ". | |
| "Groundwater" means underground water that occurs within the saturated zone and geologic materials where the fluid pressure in the pore space is equal to or greater than atmospheric pressure. [415 ILCS 5/3.210] | |
| "Hydrologic balance" means the relationship between the quality and quantity of water inflow to, water outflow from, and water storage in a hydrologic unit, such as a drainage basin, aquifer, soil zone, lake, or reservoir. It encompasses the dynamic relationships among precipitation, runoff, evaporation, and changes in ground and surface water storage. | |
| "Lowest observable adverse effect level" or "LOAEL" means the lowest tested concentration of a chemical or substance that produces a statistically significant increase in frequency or severity of non-overt adverse effects between the exposed population and its appropriate control. | |
| "Licensed Professional Engineer" or "LPE" means a person, corporation, or partnership licensed under the laws of the State of Illinois to practice professional engineering. [415 ILCS 5/57.2] | |
| "Licensed Professional Geologist" or "LPG" means an individual who is licensed under the Professional Geologist Licensing Act to engage in the practice of professional geology in Illinois. [225 ILCS 745/15] | |
| "Mutagen" means a carcinogen that can induce an alteration in the structure of DNA. | |
| "No observable adverse effect level" or "NOAEL" means the highest tested concentration of a chemical or substance that does not produce a statistically significant increase in frequency or severity of non-overt adverse effects between the exposed population and its appropriate control. | |
| "Non-community water supply" means a public water supply that is not a community water supply. [415 ILCS 5/3.145] | |
| "Off-site" means not on-site. | |
| "On-site" means on the same or geographically contiguous property that may be divided by public or private right-of-way, if the entrance and exit between properties is at a crossroads intersection and access is by crossing as opposed to going along the right-of-way. Noncontiguous properties owned by the same person but connected by a right-of-way that he or she controls and that the public does not have access to is also considered on-site property. | |
| "Operator" means the person responsible for the operation of a site, facility, or unit. | |
| "Owner" means the person who owns a site, facility, or unit, or part of a site, facility, or unit, or who owns the land on which the site, facility, or unit is located. | |
| "Potable" means generally fit for human consumption in compliance with accepted water supply principles and practices. [415 ILCS 5/3.340] | |
| "Potential primary source" means any unit at a facility or site not currently subject to a removal or remedial action that: | |
| Is used for the treatment, storage, or disposal of any hazardous or special waste not generated at the site; or | |
| Is used for the disposal of municipal waste not generated at the site, other than landscape waste and construction and demolition debris; or | |
| Is used for the landfilling, land treating, surface impounding, or piling of any hazardous or special waste that is generated on the site or at other sites owned, controlled, or operated by the same person; or | |
| Stores or accumulates at any time more than 75,000 pounds above ground, or more than 7,500 pounds below ground, of any hazardous substances. [415 ILCS 5/3.345] | |
| "Potential route" means abandoned and improperly plugged wells of all kinds, drainage wells, all injection wells, including closed loop heat pump wells, and any excavation for the discovery, development or production of stone, sand, or gravel. This term does not include closed loop heat pump wells using USP (U.S. Pharmacopeia) food grade propylene glycol. [415 ILCS 5/3.350] | |
| "Potential secondary source" means any unit at a facility or a site not currently subject to a removal or remedial action, other than a potential primary source, that: | |
| Is used for the landfilling, land treating, or surface impounding of waste that is generated on the site or at other sites owned, controlled, or operated by the same person, other than livestock and landscape waste, and construction and demolition debris; or | |
| Stores or accumulates at any time more than 25,000 but not more than 75,000 pounds above ground, or more than 2,500 but not more than 7,500 pounds below ground, of any hazardous substance; or | |
| Stores or accumulates at any time more than 25,000 gallons above ground, or more than 500 gallons below ground, of petroleum, including crude oil or any fraction of crude oil that is not otherwise specifically listed or designated as a hazardous substance; or | |
| Stores or accumulates pesticides, fertilizers, or road oils for commercial application or for distribution to retail sales outlets; or | |
| Stores or accumulates at any time more than 50,000 pounds of any de-icing agent; or | |
| Is used for handling livestock waste or for treating domestic wastewaters other than private sewage disposal systems as defined in the Private Sewage Disposal Licensing Act [225 ILCS 225]. [415 ILCS 5/3.355] |
| "Previously mined area" means land disturbed or affected by coal mining operations before February 1, 1983. | |
| BOARD NOTE: February 1, 1983, is the effective date of the Illinois Department of Natural Resources Permanent Program regulations (62 Ill. Adm. Code 1800 through 1850) implementing the Surface Coal Mining Land Conservation and Reclamation Act [225 ILCS 720], as specified in 62 Ill. Adm. Code 1700.11(c). | |
| "Property class" means the class assigned by a tax assessor to real property for real estate taxes. | |
| BOARD NOTE: The property class (rural property, residential vacant land, residential with dwelling, commercial residence, commercial business, commercial office, or industrial) is identified on the property record card maintained by the tax assessor in compliance with the Illinois Real Property Appraisal Manual (February 1987), published by the Illinois Department of Revenue, Property Tax Administration Bureau. | |
| "Public water supply" means all mains, pipes, and structures through which water is obtained and distributed to the public, including wells and well structures, intakes and cribs, pumping stations, treatment plants, reservoirs, and storage tanks and appurtenances, collectively or severally, actually used or intended for use for furnishing water for drinking or general domestic use, and that serve at least 15 service connections or that regularly serve at least 25 persons at least 60 days per year. A public water supply is either a "community water supply" or a "non-community water supply". [415 ILCS 5/3.365] | |
| "Regulated entity" means a facility or unit regulated for groundwater protection by any State or federal agency. | |
| "Regulated recharge area" means a compact geographic area, as determined by the Board under Section 17.4 of the Act, the geology of which renders a potable resource groundwater particularly susceptible to contamination. [415 ILCS 5/3.390] | |
| "Resource groundwater" means groundwater that is presently being, or in the future is capable of being, put to beneficial use by reason of being of suitable quality. [415 ILCS 5/3.430] | |
| "Setback zone" means a geographic area, designated under the Act, containing a potable water supply well or a potential source or potential route having a continuous boundary, and within which specified prohibitions or regulations apply to protect groundwaters. [415 ILCS 5/3.450] | |
| "Site" means any location, place, tract of land, and facilities, including buildings and improvements used for purposes subject to regulation or control by the Act or regulations under the Act. [415 ILCS 5/3.460] | |
| "Spring" means a natural surface discharge of an aquifer from rock or soil. | |
| "Threshold dose" means the lowest dose of a chemical at which a specified measurable effect is observed and below which it is not observed. | |
| "Treatment" means the technology, treatment techniques, or other procedures for compliance with 35 Ill. Adm. Code, Subtitle F. | |
| "Unit" means any device, mechanism, equipment, or area (exclusive of land used only for agricultural production). This term includes secondary containment structures and their contents at agrichemical facilities. [415 ILCS 5/3.515] | |
| "USEPA" means the United States Environmental Protection Agency. | |
| a) | The Board incorporates the following material by reference: |
| ASTM International. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959 (610) 832-9500. |
| "Standard Practice for Classification of Soils for Engineering Purposes (Unified Classification System)" ASTM D2487-06. | |
| "Standard Test Method for Determination of Per- and Polyfluoroalkyl Substances in Water, Sludge, Influent, Effluent, and Wastewater by Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS) ASTM D7979-20. |
| GPO. Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20401 (202) 783-3238. |
| NAS National Academy of Sciences, Engineering, and Medicine, | |
| 500 5th St. NW, Washington DC, 20001 (202) 334-2000. | |
| "Water Quality Criteria 1972", EPA.R3.73-033, 1973. https://nepis.epa.gov | |
| NCRP. National Council on Radiation Protection, 7910 Woodmont Ave., Bethesda, MD (301) 657-2652. |
| "Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure", NCRP Report Number 22, June 5, 1959. |
| USEPA, 1200 Pennsylvania Avenue, N. W., Washington DC, 20460 (202) 564-4700 |
| "Low Stress (low flow) Purging and Sampling Procedure for the Collection of Groundwater Samples from Monitoring Wells", EPA Publication EQASOP-GW4, Region 1 Low-Stress (low flow) SOP Revision No. 4, July 30, 1996; revised September 19, 2017. | |
| "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods", USEPA Publication No. SW-846, Third Edition, Final Updates I (1993), II (1995), IIA (1994), IIB (1995), III (1997), IIIA (1999), IIIB (2005), IV (2008), V (2015), VI Phase 1 (2017), VI Phase 2 (2018), VI Phase 3 (2019), and VII Phase 1 (2020). http://www.epa.gov/hw-sw846/sw-846-compendium . | |
| United States Geological Survey, 1961 Stout St., Denver, CO 80294 (303) 844-4169 |
| "Techniques of Water Resources Investigations of the United States Geological Survey, Guidelines for Collection and Field Analysis of Ground-Water Samples for Selected Unstable Constituents", Book I, Chapter D2 (1976). |
| b) | This Section incorporates no later editions or amendments. |
| Section 620.130 | Exemption from General Use Standards and Public and Food Processing Water Supply Standards |
| Section 620.135 | Exclusion for Underground Waters in Certain Man-Made Conduits |
| a) | One of the following four classes of groundwater under Sections 620.210 through 620.240: |
| 1) | Class I: Potable Resource Groundwater; |
| 2) | Class II: General Resource Groundwater; |
| 3) | Class III: Special Resource Groundwater; or |
| 4) | Class IV: Other Groundwater; |
| b) | A groundwater management zone established under Section 620.250; or |
| c) | A groundwater management zone under 35 Ill. Adm. Code 740.530. See Section 620.250(h)-(j). |
| a) | Groundwater that is 10 feet or more below the land surface and within: |
| 1) | The minimum setback zone of a well that serves as a potable water supply and to the bottom of the well; |
| 2) | Unconsolidated sand, gravel, or sand and gravel that is 5 feet or more in thickness and contains 12% or less of fines (i.e., fines that pass through a No. 200 sieve tested in compliance with ASTM Standard Practice D2487-06, incorporated by reference in Section 620.125); |
| 3) | Sandstone that is 10 feet or more in thickness or fractured carbonate that is 15 feet or more in thickness; |
| 4) | Any geologic material that is capable of a: |
| A) | Sustained groundwater yield, from up to a 12-inch borehole, of at least 150 gallons per day from a thickness of 15 feet or less; or |
| B) | Hydraulic conductivity of 1 x 10-4 cm/sec or greater using one of the following test methods or its equivalent: |
| i) | Slug test; or |
| ii) | Pump test |
| 5) | A wellhead protection area, as defined in Section 620.110, that is a Phase I or Phase II wellhead protection area delineated in compliance with the "Guidance Document for Groundwater Protection Needs Assessments" and “The Illinois Wellhead Protection Program”, both incorporated by reference in Section 620.125; or |
| 6) | The maximum setback zone of a community water supply well adopted under Section 14.3 of the Act. |
| b) | Groundwater that is determined by the Board, under the procedures specified in Section 620.260, to be capable of potable use. |
| a) | Groundwater that does not meet Section 620.210 (Class I), Section 620.230 (Class III), or Section 620.240 (Class IV); or |
| b) | Groundwater that is determined by the Board, under the procedures specified in Section 620.260, to be capable of agricultural, industrial, recreational, or other beneficial uses. |
| (Source: Amended at 49 Ill. Reg. 4488, effective March 28, 2025) | |
| a) | Groundwater that is determined by the Board, under the procedures specified in Section 620.260, to be: |
| 1) | Demonstrably unique (e.g., irreplaceable sources of groundwater) and suitable for application of a groundwater quality standard more stringent than the otherwise applicable groundwater quality standard specified in Subpart D; or |
| 2) | Vital for a particularly sensitive ecological system. |
| b) | Groundwater that contributes to a dedicated nature preserve that is listed by the Agency as specified below: |
| 1) | A written request to list a dedicated nature preserve under this subsection must contain the following information: |
| A) | A general description of the site and the surrounding land use; |
| B) | A topographic map or other map of suitable scale denoting the location of the dedicated nature preserve; |
| C) | A general description of the existing groundwater quality at and surrounding the dedicated nature preserve; |
| D) | A general geologic profile of the dedicated nature preserve based upon the most reasonably available information, including geologic maps and subsurface groundwater flow directions; and |
| E) | A description of the interrelationship between groundwater and the nature of the site. |
| 2) | Upon confirmation by the Agency of the technical adequacy of a written request, the Agency must publish the proposed listing of the dedicated nature preserve in the Environmental Register for a 45-day public comment period. Within 60 days after the close of the public comment period, the Agency must either publish a final listing of the dedicated nature preserve in the Environmental Register or provide a written response to the requestor specifying the reasons for not listing the dedicated nature preserve. |
| 3) | At least once annually, the Agency must publish in the Environmental Register a complete listing of all dedicated nature preserves listed under this subsection. |
| 4) | For this subsection "dedicated nature preserve" means a nature preserve that is dedicated under the Illinois Natural Areas Preservation Act [525 ILCS 30]. | ||
| a) | Groundwater within a zone of attenuation under 35 Ill. Adm. Code 811 and 814. |
| b) | Groundwater within a point of compliance under 35 Ill. Adm. Code 724, but not to exceed a lateral distance of 200 feet from the edge of a potential primary or secondary source. |
| c) | Groundwater that naturally contains more than 10,000 mg/L of total dissolved solids. |
| d) | Groundwater that has been designated by the Board as an exempt aquifer under 35 Ill. Adm. Code 730.104. |
| e) | Groundwater that underlies a potential primary or secondary source, in which contaminants may be present from a release, if the owner or operator of the source notifies the Agency in writing and the following conditions are met: |
| 1) | The outermost edge of what would be considered the Class IV groundwater is the closest practicable distance from the source, but does not exceed: |
| A) | A lateral distance of 25 feet from the edge of the potential source or the property boundary, whichever is less, and |
| B) | A depth of 15 feet from the bottom of the potential source or the land surface, whichever is greater; |
| 2) | The source of any release of contaminants to groundwater has been controlled; |
| 3) | Migration of contaminants within the site resulting from a release to groundwater has been minimized; |
| 4) | Any on-site release of contaminants to groundwater has been managed to prevent migration off-site; and |
| 5) | No potable water well exists within the outermost edge as specified in subsection (e)(1). |
| f) | Groundwater that underlies a coal mine refuse disposal area not contained within an area from which overburden has been removed, a coal combustion waste disposal area at a surface coal mine authorized under Section 21(s) of the Act, or an impoundment that contains sludge, slurry, or precipitated process material at a coal preparation plant, in which contaminants may be present, if the area or impoundment began operating after February 1, 1983, the owner and operator notifies the Agency in writing, and the following conditions are met: |
| 1) | The outermost edge of what would be considered the Class IV groundwater is the closest practicable distance from the area or impoundment, but does not exceed: |
| A) | A lateral distance of 25 feet from the edge of the area or impoundment, or the property boundary, whichever is less; and |
| B) | A depth of 15 feet from the bottom of the area or impoundment, or the land surface, whichever is greater; |
| 2) | The source of any release of contaminants to groundwater has been controlled; |
| 3) | Migration of contaminants within the site resulting from a release to groundwater has been minimized; |
| 4) | Any on-site release of contaminants to groundwater has been managed to prevent migration off-site; and |
| 5) | No potable water well exists within the outermost edge as specified in subsection (f)(1). |
| g) | Groundwater within a previously mined area, unless monitoring demonstrates that the groundwater is capable of consistently meeting the standards of specified in Section 620.410 or 620.420. If that capability is determined, groundwater within the previously mined area must not be considered Class IV. |
| h) | Groundwater regulated under 35 Ill. Adm. Code 845. |
| (Source: Amended at 49 Ill. Reg. 4488, effective March 28, 2025) | |
| a) | Within any class of groundwater, a groundwater management zone (GMZ) may be established as a three-dimensional region containing groundwater being managed to mitigate impairment caused by the release of one or more contaminants that is subject to a corrective action process approved by the Agency. |
| b) | Before a GMZ may be established, the owner or operator of a site at which there has been a release of one or more contaminants to groundwater must submit to the Agency a GMZ application. The application must contain the information required by Section 620.Appendix D, Parts I, II, and III, as well as any other information requested in writing by the Agency that is relevant to its review under subsection (c). |
| 1) | If the GMZ would extend off-site, the GMZ application must include each off-site property owner’s written permission to the establishment of the GMZ on its property. If effectively implementing the off-site portion of the GMZ requires accessing an off-site property, the GMZ application must also include the off-site property owner's written permission for that access. If the applicable written permission or permissions from an off-site property owner are not obtained—whether permission to establish the GMZ off-site, access the off-site property, or both—the GMZ will not include that off-site property. |
| 2) | Nothing in this subsection (b) precludes the owner or operator from including additional information in its GMZ application. |
| 3) | Nothing in this subsection (b) requires that a GMZ application be in the form specified in Section 620.Appendix D, Parts I, II, and III. |
| c) | The Agency must review each GMZ application submitted under subsection (b) and issue a written determination approving or rejecting the GMZ. |
| 1) | In determining whether to approve a GMZ, the Agency must consider the substantive information provided in support of the GMZ, the technical sufficiency of the GMZ, the likelihood that the GMZ will protect public health and the environment, and the likelihood that the GMZ’s corrective action process will, in a timely manner, result in compliance with the applicable standards specified in Section 620.410, 620.420, 620.430, or 620.440 or otherwise minimize exceedances to restore beneficial use as appropriate for the class or classes of groundwater. If the Agency rejects a GMZ, the Agency must, in its written determination, specify the reasons for the rejection. |
| 2) | A GMZ is established when the Agency issues a written determination approving the GMZ, including its corrective action process. Once a GMZ is established and before the corrective action is complete, the Agency may, as new information warrants and subject to the standards of subsection (c)(1), issue written determinations amending any part of the GMZ, including its size, the contaminants that are subject to it, and its corrective action process, as provided in this subsection (c)(2). A GMZ is amended when the Agency issues a written determination amending the GMZ. If the Agency rejects a submittal of the site owner or operator to amend the GMZ under subsection (c)(2)(i) or (c)(2)(ii), the Agency must do so in a written determination that specifies the reasons for the rejection. |
| i) | The Agency may issue a written determination directing that the site owner or operator submit to the Agency a written proposal to amend the GMZ, consistent with subsection (b). The Agency’s determination must identify the amendment to be proposed and specify the reasons why the amendment is necessary. If the owner or operator fails to submit a proposal or the Agency rejects the proposal, the Agency may terminate the GMZ under subsection (f) either on its own initiative or at the written request of the owner or operator. | |
| ii) | If it wishes to have the Agency amend the GMZ, the site owner or operator must submit to the Agency a written proposal to amend the GMZ, consistent with subsection (b). If the Agency rejects the proposal, the Agency may terminate the GMZ under subsection (f) either on its own initiative or at the written request of the owner or operator. |
| d) | When it completes the corrective action under subsection (c)(2), the site owner or operator must submit to the Agency a written demonstration that complies with subsection (d)(1) or (d)(2) and contains the information required by the completion certification specified in Section 620.Appendix D, Part IV. The Agency must review this demonstration and issue a written determination approving or rejecting the demonstration. Nothing in this subsection (d) requires the owner or operator to make the demonstration using any specific type of documentation or precludes the owner or operator from including additional information in the demonstration. . |
| 1) | The owner or operator must demonstrate that it has completed the corrective action under subsection (c)(2) and the applicable standards of Subpart D, as specified in Section 620.450(a)(4)(A), have been attained in groundwater within the GMZ. If the Agency approves this demonstration, the Agency must issue a written determination to that effect in which the Agency terminates the GMZ. The termination takes effect when the Agency issues this determination. If the Agency rejects this demonstration, the Agency must, in its written determination, specify the reasons for the rejection, which may include the Agency's basis for amending the GMZ to require additional corrective action under subsection (c)(2). |
| 2) | The owner or operator must demonstrate that it has completed the corrective action under subsection (c)(2) and concentrations of released chemical constituents, as specified in Section 620.450(a)(4)(B), remain in groundwater within the GMZ. The owner or operator must also demonstrate compliance with Section 620.450(a)(4)(B)(i) and (ii), as well as the on-going adequacy of controls, management, or both, as applicable, to maintain compliance with Section 620.450(a)(4)(B)(i) and (ii). If the Agency approves this demonstration, the Agency must issue a written determination to that effect in which the Agency states that the GMZ remains in effect. If the Agency rejects this demonstration, the Agency must, in its written determination, specify the reasons for the rejection, which may include the Agency's basis for amending the GMZ to require additional corrective action under subsection (c)(2). |
| e) | Within five years after the Agency issues a written determination approving a demonstration under subsection (d)(2), the site owner or operator must submit a report to the Agency demonstrating the on-going adequacy of controls, management, or both, as applicable, to maintain compliance with Section 620.450(a)(4)(B)(i) and (ii). The Agency must review the report and issue a written determination approving or rejecting the demonstration. |
| 1) | The submittal of these reports by the owner or operator and the corresponding issuance of these written determinations by the Agency must occur at least every five years while the GMZ remains in effect. If the Agency rejects a demonstration, the Agency must, in its written determination, specify the reasons for the rejection, which may include the Agency’s basis for amending the GMZ to require additional controls or management under this subsection (e). |
| 2) | Any amendment to controls or management under this subsection (e) is subject to the amendment provisions of subsection (c)(2), except that the standard for the Agency’s determination is whether the controls or management, as amended, would be adequate to maintain compliance with Section 620.450(a)(4)(B)(i) and (ii). |
| f) | Without limiting any other legal authority of the Agency to terminate a GMZ, the Agency may issue a written determination terminating a GMZ based on any of the grounds specified in this subsection (f). The determination must specify the grounds for terminating the GMZ. The termination takes effect when the Agency issues this determination. The Agency may terminate a GMZ if: |
| 1) | The site owner or operator fails to perform or comply with the schedule for any part of the GMZ, including its corrective action under subsection (c)(2) or its controls or management under subsection (d)(2) or (e); |
| 2) | The Agency rejects a proposal to amend the GMZ under subsection (c)(2) or a demonstration under subsection (d) or (e); |
| 3) | The site owner or operator commits fraud or misrepresentation in any submittal under subsection (b), (c)(2), (d), or (e); |
| 4) | The site owner or operator submits to the Agency a written request to terminate the GMZ under subsection (c)(2); or |
| 5) | The Agency, after issuing a written determination approving a demonstration under subsection (d)(2), determines that |
| i) | The applicable standards specified in Section 620.410, 620.420, 620.430, or 620.440 have been attained in groundwater within the GMZ; or |
| ii) | Additional corrective action is necessary because controls and management are no longer adequate to maintain compliance with Section 620.450(a)(4)(B)(i) and (ii). |
| g) | Upon GMZ termination under subsection (f), the groundwater within the three-dimensional region formerly encompassed by the GMZ becomes both designated as one of the four classes of groundwater specified in Section 620.201(a) and subject to the standards for the applicable class of groundwater specified in Section 620.410, 620.420, 620.430, or 620.440. |
| h) | Regardless of subsections (a) through (c), a "groundwater management zone", as defined in 35 Ill. Adm. Code 740.120, may be established under 35 Ill. Adm. Code 740.530 for sites in the Site Remediation Program (35 Ill. Adm. Code 740). A GMZ established under 35 Ill. Adm. Code 740.530 remains in effect until any condition of 35 Ill. Adm. Code 740.530(c) is met. |
| i) | While a GMZ established under 35 Ill. Adm. Code 740.530 is in effect, the otherwise applicable standards of Subpart D of this Part do not apply to the “contaminants of concern”, as defined in 35 Ill. Adm. Code 740.120, for which groundwater remediation objectives have been approved under 35 Ill. Adm. Code 740. |
| j) | Regardless of subsection (d), that subsection’s submittal and review requirements concerning the demonstration when corrective action is complete do not apply to a GMZ under 35 Ill. Adm. Code 740.530. Regardless of subsection (e), that subsection's submittal and review requirements concerning the on-going adequacy of controls and management do not apply to groundwater within a three-dimensional region formerly encompassed by a GMZ established under 35 Ill. Adm. Code 740.530 while a No Further Remediation Letter issued under 35 Ill. Adm. Code 740 is in effect. |
| k) | The Agency must develop and maintain a list of all GMZs that have not been terminated. The list must identify the location of each GMZ. On its website (https://epa.illinois.gov ), the Agency must post the list and, at least annually, update it. In addition, at least annually, the Agency must submit the list to the Board for publication in the Environmental Register. |
| l) | In groundwater regulated under 35 Ill. Adm. Code 845, a GMZ is not available to address any exceedance of a groundwater protection standard specified in 35 Ill. Adm. Code 845.600(a) or (b) (see 35 Ill. Adm. Code 845.600(c)). |
| (Source: Amended at 49 Ill. Reg. 4488, effective March 28, 2025) |
| a) | The specific groundwater for which reclassification is requested, including geographical extent of any aquifers, depth of groundwater, and rate and direction of groundwater flow, and that the specific groundwater exhibits the characteristics of the requested class specified in Section 620.210(b), 620.220(b), 620.230, or 620.240; |
| b) | Whether the proposed change or use restriction is necessary for economic or social development, including information concerning any negative economic or social impacts of compliance with the currently applicable groundwater quality standards (e.g., job losses, facility closings), as well as an economic analysis contrasting the costs of meeting the current standards with cost savings due to health and environmental benefits resulting from compliance with those standards; |
| c) | Existing and anticipated uses of the specific groundwater; |
| d) | Existing and anticipated quality of the specific groundwater; |
| e) | Existing and anticipated contamination, if any, of the specific groundwater; |
| f) | Technical feasibility and economic reasonableness of eliminating or reducing contamination of the specific groundwater or of maintaining existing water quality; |
| g) | The anticipated time period over which contaminants will continue to affect the specific groundwater; |
| h) | Existing and anticipated impact on any potable water supplies due to contamination; |
| i) | Availability and cost of alternate water sources or of treatment for users adversely affected; |
| j) | Negative or positive effect on property values; and |
| k) | For special resource groundwater, negative or positive effect on: |
| 1) | The quality of surface waters; and |
| 2) | Wetlands, natural areas, and the life contained in wetlands and natural areas, including endangered or threatened species of plant, fish, or wildlife listed under the Endangered Species Act, 16 U.S.C. 1531 et seq., or the Illinois Endangered Species Protection Act [520 ILCS 10]. |
| a) | A person must not cause, threaten, or allow the release of any contaminant to a resource groundwater such that: |
| 1) | Treatment or additional treatment is necessary to continue an existing use or to assure a potential use of the groundwater; or |
| 2) | An existing or potential use of the groundwater is precluded. |
| b) | Nothing in this Section prevents the establishment of a groundwater management zone under Section 620.250 or a cumulative impact area within a permitted site. |
| c) | Nothing in this Section limits underground injection in compliance with an underground injection control program administered by the Agency under the Act, by the Department of Natural Resources, Office of Mines and Minerals under the Illinois Oil and Gas Act (225 ILCS 725), or by USEPA under the federal UIC regulations [40 CFR 144]. |
| d) | Nothing in this Section limits the Board from promulgating nondegradation provisions applicable to types of facilities or activities that impact groundwater, including landfills regulated under 35 Ill. Adm. Code: Subtitle G. |
| a) | Preventive notification and preventive response activities, as specified in Sections 620.305 through 620.310, apply to: |
| 1) | Class I groundwater under Section 620.210(a)(1), (a)(2), (a)(3), (a)(5), or (a)(6) that is monitored by any person specified in subsection (b); and |
| 2) | Class III groundwater that is monitored by any person specified in subsection (b). |
| b) | For subsection (a), the persons that conduct groundwater monitoring are: |
| 1) | An owner or operator of a regulated entity required to perform groundwater quality monitoring under State or federal law or regulation; |
| 2) | An owner or operator of a public water supply well who conducts groundwater quality monitoring; |
| 3) | A State agency that is authorized to conduct, or is the recipient of, groundwater quality monitoring data (e.g., Illinois Environmental Protection Agency, Department of Public Health, Department of Agriculture, Office of State Fire Marshal, or Department of Natural Resources); or |
| 4) | An owner or operator of a facility that conducts groundwater quality monitoring under State or federal judicial or administrative order. |
| c) | If a contaminant exceeds a standard specified in Section 620.410 or Section 620.430, the appropriate remedy is corrective action and Sections 620.305 and 620.310 do not apply. |
| a) | For groundwater quality monitoring under Section 620.302, a preventive notification must occur whenever a contaminant: |
| 1) | Specified in Section 620.310(a)(3)(A) is detected (except due to natural causes) in Class I groundwater; |
| 2) | Denoted as a carcinogen under Section 620.410(b) is detected in Class I groundwater; or |
| 3) | Subject to a standard under Section 620.430 is detected (except due to natural causes) in Class III groundwater. |
| b) | When a preventive notification is required for groundwater that is monitored by a regulated entity for the subject contaminant, the owner or operator of the site must: |
| 1) | Confirm the detection by resampling the monitoring well within 30 days after the date on which the first sample analyses are received; and |
| 2) | Provide a preventive notification to the appropriate regulatory agency of the results of the resampling analysis within 30 days after the date on which the sample analyses are received, but no later than 90 days after the results of the first samples were received. |
| c) | When a preventive notification is required for groundwater that is monitored by a regulatory agency, the agency must notify the owner or operator of the site where the detection has occurred. The owner or operator must: |
| 1) | Confirm the detection by resampling within 30 days after the date of the notice by the regulatory agency; and |
| 2) | Provide preventive notification to the regulatory agency of the results of the resampling analysis within 30 days after the date on which the sample analyses are received, but no later than 90 days after the results of the first samples were received. |
| d) | When a preventive notification of a confirmed detection has been provided by an owner or operator under this Section, additional detections of the same contaminant do not require further notice if the groundwater quality conditions are substantially unchanged or that preventive response is underway for the contaminant. |
| a) | The following preventive assessment must be undertaken: |
| 1) | If a preventive notification under Section 620.305(c) is provided by a community water supply: |
| A) | The Agency must notify the owner or operator of any identified potential primary source, potential secondary source, potential route, or community water supply well that is within 2,500 feet of the wellhead. |
| B) | The owner or operator notified under subsection (a)(1)(A) must, within 30 days after the date of issuance of that notice, sample each water well or monitoring well for the contaminant identified in the notice if the contaminant or material containing the contaminant is or has been stored, disposed of, or otherwise handled at the site. If a contaminant identified under Section 620.305(a) is detected, then the well must be resampled within 30 days after the date on which the first sample results are received. If a contaminant identified under Section 620.305(a) is detected by the resampling, preventive notification must be given as specified in Section 620.305. |
| C) | If the Agency receives analytical results under subsection (a)(1)(B) that show a contaminant identified under Section 620.305(a) has been detected, the Agency must: |
| i) | Conduct a well site survey under Section 17.1(d) of the Act[415 ILCS 5/17.1(d)] if one has not been conducted within the last 5 years; and |
| ii) | Identify those sites or activities that represent a hazard to the continued availability of groundwaters for public use unless a groundwater protection needs assessment has been prepared under Section 17.1(d) of the Act. |
| 2) | If a preventive notification is provided under Section 620.305(c) by a non-community water supply or for multiple private water supply wells, the Department of Public Health must conduct a sanitary survey within 1,000 feet of the wellhead of a non-community water supply or within 500 feet of the wellheads for multiple private water supply wells. |
| 3) | If a preventive notification under Section 620.305(b) is provided by the owner or operator of a regulated entity and the applicable standard of Subpart D has not been exceeded, the appropriate regulatory agency must: |
| A) | Determine if any of the following occurs for Class I: Potable Resource Groundwater: |
| i) | The levels specified below are exceeded or are changed for pH: |
| CASRN | Constituent | Criteria (mg/L) |
| 95-50-1 | o-Dichlorobenzene (1,2-dichlorobenzene) | 0.01 | |
| 1634-04-4 | MTBE methyl tertiary
butyl ether |
0.02 | |
| 108-95-2 | Phenols | 0.001 | |
| 100-42-5 | Styrene | 0.01 | |
| 108-88-3 | Toluene | 0.04 | |
| 1330-20-7 | Xylenes | 0.02 |
CASRN Constituent
Inorganics
7429-90-5 Aluminum
7440-38-2 Arsenic
7440-41-7 Beryllium
7440-43-9 Cadmium
7440-47-3 Chromium (total)
143-33-9 Cyanide
7439-92-1 Lead
7487-94-7 Mercury (mercuric chloride)
7439-98-7 Molybdenum
7440-28-0 Thallium
7440-62-2 Vanadium
Organics
83-32-9 Acenaphthene
67-64-1 Acetone
116-06-3 Aldicarb
120-12-7 Anthracene
319-84-6 alpha-BHC (alpha-benzene
hexachloride)
1912-24-9 Atrazine and metabolites DEA, DIA,
DACT
71-43-2 Benzene
56-55-3 Benzo(a)anthracene
205-99-2 Benzo(b)fluoranthene
207-08-9 Benzo(k)fluoranthene
50-32-8 Benzo(a)pyrene
65-85-0 Benzoic acid
78-93-3 2-Butanone (methyl ethyl ketone)
1563-66-2 Carbofuran
75-15-0 Carbon disulfide
56-23-5 Carbon tetrachloride
12789-03-6 Chlordane
108-90-7 Chlorobenzene
67-66-3 Chloroform
218-01-9 Chrysene
94-75-7 2.4-D (2.4-dichlorophenoxy
acetic acid)
75-99-0 Dalapon
96-12-8 1,2-Dibromo-3-chloropropane
(dibromochloroorooane)
1918-00-9 Dicamba
106-46-7 p-Dichlorobenzene (1,4-
dichlorobenzene)
75-71-8 Dichlorodifluoromethane
75-34-3 1,1-Dichloroethane
75-35-4 1,1-Dichloroethylene
107-06-2 1,2-Dichloroethane
156-59-2 cis-1,2-Dichloroethylene
156-60-5 trans-1,2-Dichloroethylene
75-09-2 Dichloromethane (methylene
chloride)
78-87-5 1,2-Dichloropropane
117-81-7 Di(2-ethylhexyl)phthalate
84-66-2 Diethyl phthalate
84-74-2 Di-n-butyl phthalate
99-65-0 1,3-Dinitrobenzene
121-14-2 2,4-Dinitrotoluene
88-85-7 Dinoseb
123-91-1 1,4-Dioxane (p dioxane)
145-73-3 Endothall
72-20-8 Endrin
100-41-4 Ethylbenzene
106-93-4 Ethylene dibromide (1,2-
dibromoethane)
206-44-0 Fluoranthene
86-73-7 Fluorene
58-89-9 gamma-HCH (gamma-
hexachlorocyclohexane lindane)
13252-13-6 HFPO-DA (hexafluoropropylene
oxide dimer acid, GenX)
2691-41-0 HMX (octahydro-1,3,5,7-
tetranitro-1, 3, 5, 7-tetrazocine)
76-44-8 Heptachlor
1024-57-3 Heptachlor epoxide
77-47-4 Hexachlorocyclopentadiene
193-39-5 Indeno(l,2,3-c,d)pyrene
98-82-8 Isopropylbenzene (cumene)
72-43-5 Methoxychlor
90-12-0 1-Methylnaphthalene
91-57-6 2-Methylnaphthalene
95-48-7 2-Methylphenol (o-cresol)
91-20-3 Naphthalene
98-95-3 Nitrobenzene
1336-36-3 PCBs (polychlorinated
biphenyls as decachloro-
biphenyl)
375-73-5 PFBS (perfluorobutanesulfonic acid)
355-46-4 PFHxS (perfluorohexanesulfonic
acid)
375-95-1 PFNA (perfluorononanoic acid)
335-67-1 PFOA (perfluorooctanoic acid)
1763-23-1 PFOS (perfluorooctanesulfonic
acid)
87-86-5 Pentachlorophenol
1918-02-1 Picloram
129-00-0 Pyrene
121-82-4 RDX (hexahydro-1,3,5-trinitro-
1,3,5-triazine)
122-34-9 Simazine
118-96-7 TNT (2,4,6-trinitrotoluene)
93-72-1 2,4,5-TP (silvex)
127-18-4 Tetrachloroethylene
8001-35-2 Toxaphene
120-82-1 1,2,4-Trichlorobenzene
71-55-6 1,1,1-Trichloroethane
79-00-5 1,1,2-Trichloroethane
79-01-6 Trichloroethylene
75-69-4 Trichlorotluoromethane
99-35-4 1,3,5-Trinitrobenzene
75-01-4 Vinyl chloride
iii) For a chemical constituent of gasoline, diesel fuel, or heating fuel, the constituent exceeds the following:
| Constituent | Criterion (mg/L) |
| BETX | 0.095 |
CASRN Constituent Standard
(mg/L) a,b
7429-90-5 Aluminum l.9c
7440-36-0 Antimony 0.006d
7440-38-2 Arsenice 0.01d
7440-39-3 Barium 2.0d
7440-41-7 Beryllium 0.004d
7440-42-8 Boron 2.0f
7440-43-9 Cadmium 0.005d
16887-00-6 Chloride 200g
7440-47-3 Chromium (total) 0.ld
7440-48-4 Cobalt 0.0012c
7440-50-8 Copper 0.5h
143-33-9 Cyanide 0.2d
7681-49-4 Fluoride 4d
7439-89-6 Iron 5g
7439-92-1 Lead 0.0075i
7439-93-2 Lithium 0.04j
7439-96-5 Manganese 0.l5k
7487-94-7 Mercury (mercuric chloride) 0.002d
7439-98-7 Molybdenum 0.308c
7440-02-0 Nickel 0.077c
14797-55-8 Nitrate as N 10d
14797-73-0 Perchlorate 0.0081c
7440-14-4 Radium (combined 226+228) 5d
7782-49-2 Selenium 0.02f
7440-22-4 Silver 0.058c
14808-79-8 Sulfate 400g
TDS (total dissolved solids) 1,200g
7440-28-0 Thallium 0.002d
7440-62-2 Vanadium 0.00027c
7440-66-6 Zinc l.2c
Constituent Name and Groundwater Quality Standard Notations
a The standard unit for radium (combined 226+228) is picocuries per liter (pCi/L).
b The inorganic groundwater quality standards are based on total metal analyses for the evaluation of human health effects.
c The standard is calculated using the Human Threshold Toxicant Advisory Concentration (HTTAC) procedures at Appendix A.
d The standard is based on the Maximum Contaminant Level (MCL), promulgated by USEPA, Office of Water, and Illinois Primary Drinking Water Standards specified in 35 Ill. Adm. Code 611.
e The constituent meets the definition of a "carcinogen" in Section 620.110.
f The standard is based on beneficial use for irrigation of crops, per "Water Quality Criteria", by National Academy of Sciences, incorporated by reference in Section 620.125.
g The standard is the 95% confidence concentration stated in the Agency's "Integrated Water Quality Report and Section 303(d) List", incorporated by reference in Section 620.125.
h The standard is based on beneficial use for watering livestock, per "Water Quality Criteria", by National Academy of Sciences, incorporated by reference in Section 620.125.
i The standard is 50% of the USEPA "action level" of 0.015 mg/L for lead. The USEPA action level applies at the service connection. The standard is reduced by 50% as a safety margin, based on the assumption that 50% of water would be treated.
j The standard is the "LLOQ" or "LCMRL" as defined in Section 620.110.
k The standard is promulgated at 35 Ill. Adm. Code 611.300.
b) Organic Chemical Constituents
Except due to natural causes or as provided in Section 620.450 or subsection (c) of this Section, concentrations of the following organic chemical constituents must not be exceeded in Class I groundwater:
CASRN Constituent Standard
(mg/L)
83-32-9 Acenaphthene 0.23a
67-64-1 Acetone 3.5a
15972-60-8 Alachlorb 0.002c
116-06-3 Aldicarb 0.003c
120-12-7 Anthracene 1.2a
319-84-6 alpha-BHC (alpha-benzene 0.000012d
hexachloride)b
71-43-2 Benzeneb 0.005c
56-55-3 Benzo(a)anthracenee 0.00025d
205-99-2 Benzo(b)fluoranthenee 0.00025d
207-08-9 Benzo(k)fluoranthenee 0.0025d
50-32-8 Benzo(a)pyrenee 0.0002c
65-85-0 Benzoic acid 15a
78-93-3 2-Butanone (methyl ethyl ketone) 2.3a
1563-66-2 Carbofuran 0.04c
75-15-0 Carbon disulfide 0.38a
56-23-5 Carbon tetrachlorideb 0.005c
12789-03-6 Chlordaneb 0.002c
108-90-7 Chlorobenzene 0.lc
67-66-3 Chloroformb 0.07f
218-01-9 Chrysenee 0.025d
94-75-7 2,4-D (2,4-dichlorophenoxy 0.07c
acetic acid)
75-99-0 Dalapon 0.2c
53-70-3 Dibenzo(a,h)anthracenee 0.0001g
96-12-8 1,2-Dibromo-3-chloropropane 0.0002c
(dibromochloropropane)e
1918-00-9 Dicamba 0.12a
95-50-1 o-Dichlorobenzene (1,2- 0.6c
dichlorobenzene)
106-46-7 p-Dichlorobenzene (1,4- 0.075c
dichlorobenzene)b
75-71-8 Dichlorodifluoromethane 0.77a
75-34-3 1,1-Dichloroethane 0.77a
107-06-2 1,2-Dichloroethaneb 0.005c
75-35-4 1,1-Dichloroethylene 0.007c
156-59-2 cis-1,2-Dichloroethylene 0.07c
156-60-5 trans-1,2-Dichloroethylene 0.lc
75-09-2 Dichloromethane (methylene 0.005c
chloride)e
78-87-5 1,2-Dichloropropaneb 0.005c
117-81-7 Di(2-ethylhexyl)phthalateb 0.006c
84-66-2 Diethyl phthalate 3.1a
84-74-2 Di-n-butyl phthalate 0.38a
99-65-0 1,3-Dinitrobenzene 0.001g
121-14-2 2,4-Dinitrotolueneb 0.001g
606-20-2 2,6-Dinitrotolueneb 0.0001g
88-85-7 Dinoseb 0.007c
123-91-1 1,4-Dioxane (p-dioxane)b 0.00078d
145-73-3 Endothall 0.lc
72-20-8 Endrin 0.002c
100-41-4 Ethylbenzeneb 0.7c
106-93-4 Ethylene dibromide (1,2- 0.00005c
dibromoethane)b
206-44-0 Fluoranthene 0.15a
86-73-7 Fluorene 0.15a
58-89-9 gamma-HCH (gamma- 0.0002c
Hexachlorocyclohexane, lindane)b
13252-13-6 HFPO-DA (hexafluoropropylene 0.000010c
oxide dimer acid GenX)
2691-41-0 HMX (octahydro-1,3,5,7- 0.77a
tetranitro-1,3,5,7-tetrazocine)
76-44-8 Heptachlorb 0.0004c
1024-57-3 Heptachlor epoxideb 0.0002c
77-47-4 Hexachlorocyclopentadiene 0.05c
193-39-5 Indeno(l,2,3-c,d)pyrenee 0.00025d
98-82-8 Isopropylbenzene (cumene)b 0.38a
93-65-2 MCPP (mecoprop) 0.1g
1634-04-4 MTBE (methyl tertiary- 0.038a
butyl ether)
72-43-5 Methoxychlor 0.04c
90-12-0 1-Methylnaphthalene 0.27a
91-57-6 2-Methylnaphthalene 0.015c
95-48-7 2-Methylphenol (o-cresol) 0.19a
91-20-3 Naphthalene 0.077a
98-95-3 Nitrobenzene 0.0077a
1336-36-3 PCBs (polychlorinated biphenyls 0.0005c
as decachloro-biphenyl)b
375-73-5 PFBS (perfluorobutanesulfonic 0.002c
acid)
355-46-4 PFHxS (perfluorohexanesulfonic 0.000010c
acid)
375-95-1 PFNA (perfluorononanoic acid) 0.000010c
335-67-1 PFOA (perfluorooctanoic acid)b 0.000004bc
1763-23-1 PFOS (perfluorooctanesulfonic 0.000004bc
acid)
87-86-5 Pentachlorophenol 0.001c
108-95-2 Phenol 0.1h
1918-02-1 Picloram 0.5c
129-00-0 Pyrene 0.12a
121-82-4 RDX (hexahydro-1,3,5-trinitro- 0.062a
1,3,5-triazine)
122-34-9 Simazine 0.004c
100-42-5 Styrene 0.lc
118-96-7 TNT (2,4,6-trinitrotoluene) 0.0077a
93-72-1 2,4,5-TP (silvex) 0.05c
127-18-4 Tetrachloroethyleneb 0.005c
108-88-3 Toluene 1c
8001-35-2 Toxapheneb 0.003c
120-82-1 1,2,4-Trichlorobenzene 0.07c
71-55-6 1,1,1-Trichloroethane 0.2c
79-00-5 1,1,2-Trichloroethane 0.005c
79-01-6 Trichloroethylenee 0.005c
75-69-4 Trichlorofluoromethane 1.2a
99-35-4 1,3,5-Trinitrobenzene 0.46a
75-01-4 Vinyl chloridee 0.002c
1330-20-7 Xylenes 10c
Constituent Name and Groundwater Quality Standard Notations
a The standard is the Human Threshold Toxicant Advisory Concentration (HTTAC), calculated using procedures specified in Appendix A.
b The constituent meets the definition of a "carcinogen" in Section 620.110.
c The standard is based on the Maximum Contaminant Level (MCL), promulgated by USEPA, Office of Water, and Illinois Primary Drinking Water Standards in 35 Ill. Adm. Code 611.
d The standard is the Human Nonthreshold Toxicant Advisory Concentration ("HNTAC"), calculated using procedures specified in Appendix A.
e The constituent meets the definition of a "mutagen" in Section 620.110.
f The standard is based on the Maximum Contaminant Level Goal ("MCLG"), promulgated by USEPA, Office of Water.
g The standard is the "LLOQ" or "LCMRL" as defined in Section 620.110.
h The standard is based on 35 Ill. Adm. Code 302.208.
c) Complex Organic Chemical Mixtures
1) Concentrations of the following chemical constituents must not be exceeded in Class I groundwater:
CASRN Constituent Standard
(mg/L)
71-43-2 Benzenea 0.005b
Total BETX 11.705c
Constituent Name and Groundwater Quality Standard Notations
a The constituent meets the definition of a "carcinogen" in Section 620.110.
b The standard is based on the Maximum Contaminant Level (MCL), promulgated by USEPA, Office of Water, and Illinois Primary Drinking Water Standards at 35 Ill. Adm. Code 611.
c The standard is the total combined standard of benzene, ethylbenzene, toluene, and xylenes.
2) Atrazine and Metabolites
Concentrations of the following chemical constituents must not be exceeded in Class I groundwater.
CASRN Constituent Standard
(mg/L)
1912-24-9 Atrazine 0.003a
Total Atrazine and 0.003
Metabolites
6190-65-4 DEA (desethyl-atrazine)
1007-28-9 DIA (desisopropyl-atrazine)
3397-62-4 DACT (diaminochlorotriazine)
Groundwater Quality Standard Notation
aThe standard is based on the Maximum Contaminant Level (MCL), promulgated by USEPA, Office of Water, and Illinois Primary Drinking Water Standards at 35 Ill. Adm. Code 611.
d) pH
Except due to natural causes, a pH range of 6.5 - 9.0 units must not be exceeded in Class I groundwater.
e) Beta Particle and Photon Radioactivity
1) Except due to natural causes, the average annual concentration of beta particle and photon radioactivity from man-made radionuclides must not exceed a dose equivalent to the total body or any internal organ greater than 4 mrem/year in Class I groundwater. If two or more radionuclides are present, the sum of their dose equivalent to the total body or any internal organ must not exceed 4 mrem/year in Class I groundwater except due to natural causes.
2) Except for the radionuclides specified in subsection (e)(3), the concentration of man-made radionuclides causing 4 mrem total body or organ dose equivalent must be calculated on the basis of a 2 liter per day drinking water intake using the 168-hour data in compliance with the procedure specified in NCRP Report Number 22, incorporated by reference in Section 620.125(a).
3) Except due to natural causes, the average annual concentration assumed to produce a total body or organ dose of 4 mrem/year of the following chemical constituents must not be exceeded in Class I groundwater:
CASRN Constituent Critical Organ Standard (pCi/L)
10028-17-8 Tritium Total Body 20,000
10098-97-2 Strontium-90 Bone Marrow 8.0
f) No facility that is subject to 35 Ill. Adm. Code 811 or 814 must comply with any requirement or standard of those rules to the extent it incorporates or is otherwise based on any of the following constituents or their standards under this Section:
CASRN Constituent
13252-13-6 HFPO-DA (hexafluoropropylene
oxide dimer acid GenX)
375-73-5 PFBS (perfluorobutanesulfonic
acid)
355-46-4 PFHxS (perfluorohexanesulfonic
acid)
375-95-1 PFNA (perfluorononanoic acid)
335-67-1 PFOA (perfluorooctanoic acid)
1763-23-1 PFOS (perfluorooctanesulfonic
acid)
(Source: Amended at 49 Ill. Reg. 4488, effective March 28, 2025)
Section 620.420 Groundwater Quality Standards for Class II: General Resource Groundwater
a) Inorganic Chemical Constituents
1) Except due to natural causes or as provided in Section 620.450 or subsection (a)(3) or (e) of this Section, concentrations of the following chemical constituents must not be exceeded in Class II groundwater:
CASRN Constituent Standard
(mg/L)a
7440-36-0 Antimony 0.024b
7440-38-2 Arsenicb 0.2d
7440-39-3 Barium 2.0e
7440-41-7 Beryllium 0.5f
7440-43-9 Cadmium 0.05g
7440-47-3 Chromium (total) 1.0g
7440-48-4 Cobalt 1d
143-33-9 Cyanide 0.6d
7681-49-4 Fluoride 4e
7439-92-1 Lead 1.0d
7439-93-2 Lithium 2.5f
7487-94-7 Mercury (mercuric 0.01d
chloride)
7439-98-7 Molybdenum 0.308e
14797-55-8 Nitrate as N 100d
14797-73-0 Perchlorate 0.0081e
7440-28-0 Thallium 0.02h
7440-62-2 Vanadium 0.1d
Constituent Name and Groundwater Quality Standard Notations
a The inorganic groundwater quality standards are based on total metal analyses for the evaluation of human health effects.
b A treatment factor of 4 is applied to the Class I groundwater quality standard. The constituent’s treatment efficiency is based on the effectiveness to treat the constituent in the groundwater at an 75% removal efficiency rate for the constituent.
c The constituent meets the definition of a "carcinogen" in Section 620.110.
d The standard is based on beneficial use for watering livestock, per "Water Quality Criteria", by National Academy of Sciences, incorporated by reference in Section 620.125.
e The Class II standard is equal to the Class I groundwater quality standard.
f The standard is based on beneficial use for irrigation of crops, per "Water Quality Criteria", by National Academy of Sciences, incorporated by reference in Section 620.125.
g The standard is based on beneficial use for watering livestock and irrigation of crops, per "Water Quality Criteria", by National Academy of Sciences, incorporated by reference in Section 620.125.
h A treatment factor of 10 is applied to the Class I groundwater quality standard. The constituent’s treatment efficiency is based on the effectiveness to treat the constituent in the groundwater at an 90% removal efficiency rate for the constituent.
2) Except as provided in Section 620.450 or subsection (a)(3) or (e) of this Section, concentrations of the following chemical constituents must not be exceeded in Class II groundwater:
CASRN Constituent Standard
(mg/L)a,b
7429-90-5 Aluminum 5c
7440-42-8 Boron 2d
16887-00-6 Chloride 200e
7440-50-8 Copper 0.5c
7439-89-6 Iron 5e
7439-96-5 Manganese 10d
7440-02-0 Nickel 2d
7440-14-4 Radium 5f
(combined 226+228)
7782-49-2 Selenium 0.02d
7440-22-4 Silver 0.058f
14808-79-8 Sulfate 400e
TDS (total 1,200e
dissolved solids)
7440-66-6 Zinc 10d
Constituent Name and Groundwater Quality Standard Notations
a The standard units for radium (combined 226+228) is picocuries per liter (pCi/L).
b The inorganic groundwater quality standards are based on total metal analyses for the evaluation of human health effects.
c The standard is based on beneficial use for watering livestock and irrigation of crops, per "Water Quality Criteria", by National Academy of Sciences, incorporated by reference in Section 620.125.
d The standard is based on beneficial use for irrigation of crops, per "Water Quality Criteria", by National Academy of Sciences, incorporated by reference in Section 620.125.
e The standard is the 95% confidence concentration stated in the Agency's "Integrated Water Quality Report and Section 303(d) List", incorporated by reference in Section 620.125.
f The Class II standard is equal to the Class I groundwater quality standard.
3) The standard for any inorganic chemical constituent specified in subsection (a)(2) and barium specified in subsection (a)(1) does not apply within fill material or within the upper 10 feet of parent material under fill material on a site not within the rural property class for which the conditions of subsection (a)(3)(A) or (a)(3)(B) are met. For pH, the standard specified in subsection (d) does not apply to groundwater within fill material below 5 feet of land surface or within the upper 10 feet of parent material under fill material on a site not within the rural property class for which the conditions of subsection (a)(3)(A) or (a)(3)(B) are met.
A) Before November 25, 1991, surficial characteristics have been altered by placing the fill material so as to impact the concentration of any parameter (constituent or pH) specified in this subsection (a)(3), and any on-site groundwater monitoring of the parameter is available for review by the Agency.
B) On November 25, 1991, surficial characteristics are in the process of being altered by placing the fill material, in a reasonably continuous manner to completion, so as to impact the concentration of any parameter (constituent or pH) specified in this subsection (a)(3), and any on-site groundwater monitoring of the parameter is available for review by the Agency.
4) For subsection (a)(3), the term "fill material" means clean earthen materials, slag, ash, clean demolition debris, or similar materials.
b) Organic Chemical Constituents
1) Except due to natural causes or as provided in Section 620.450 or subsection (b)(2) or (e) of this Section, concentrations of the following organic chemical constituents must not be exceeded in Class II groundwater:
CASRN Constituent Standard
(mg/L)
83-32-9 Acenaphthene 1.2a
67-64-1 Acetone 3.5b
15972-60-8 Alachlorc 0.01a
116-06-3 Aldicarb 0.015a
120-12-7 Anthracene 6a
319-84-6 alpha-BHC 0.00006a
(alpha-benzenehexachloride)c
71-43-2 Benzenec 0.025a
56-55-3 Benzo(a)anthracened 0.0012a
205-99-2 Benzo(b)fluoranthened 0.0012a
207-08-9 Benzo(k)fluoranthened 0.012a
50-32-8 Benzo(a)pyrened 0.002e
65-85-0 Benzoic acid 15b
78-93-3 2-Butanone (methyl 2.3b
ethyl ketone)
1563-66-2 Carbofuran 0.2a
75-15-0 Carbon disulfide 1.9a
56-23-5 Carbon tetrachloridec 0.025a
12789-03-6 Chlordanec 0.01a
108-90-7 Chlorobenzene 0.5a
67-66-3 Chloroformc 0.35a
218-01-9 Chrysened 0.12a
94-75-7 2,4-D (2,4-dichloroohenoxy 0.35a
acetic acid)
75-99-0 Dalapon 2.0e
53-70-3 Dibenzo(a,h)anthracened 0.0005a
96-12-8 1,2-Dibromo-3- 0.002e
chloropropaned
1918-00-9 Dicamba 0.12b
95-50-1 o-Dichlorobenzene 1.5f
(1,2-dichlorobenzene)
106-46-7 p-Dichlorobenzene 0.375a
(1,4-dichlorobenzene)c
75-71-8 Dichlorodifluoromethane 3.9a
75-34-3 1,1-Dichloroethane 3.9a
107-06-2 1,2-Dichloroethanec 0.025a
75-35-4 1,1-Dichloroethylene 0.035a
156-59-2 cis-1,2-Dichloroethylene 0.2g
156-60-5 trans-1,2-Dichloroethylene 0.5a
75-09-2 Dichloromethane 0.025a
(methylene chloride)d
78-87-5 1,2-Dichloropropaneb 0.025a
117-81-7 Di(2-ethylhexyl)phthalateb 0.06e
84-66-2 Diethyl phthalate 3.1b
84-74-2 Di-n-butyl phthalate 1.9a
99-65-0 1,3-Dinitrobenzene 0.001b
121-14-2 2,4-Dinitrotoluenec 0.005a
606-20-2 2,6-Dinitrotoluenec 0.005a
88-85-7 Dinoseb 0.07e
123-91-1 1,4-Dioxane (p-dioxane)c 0.00078b
145-73-3 Endothall 0.1b
72-20-8 Endrin 0.01a
100-41-4 Ethylbenzenec 1.0h
106-93-4 Ethylene dibromide 0.0005e
(1,2-dibromoethane)c
206-44-0 Fluoranthene 0.75a
86-73-7 Fluorene 0.75a
58-89-9 gamma-HCH (gamma- 0.001a
hexachlorocyclohexane, lindane)c
13252-13-6 HFPO-DA 0.000010b
(hexafluoropropylene oxide
dimer acid GenX)
2691-41-0 HMX (octahydro- 3.9a
1,3,5,7-tetranitro-
1,3,5,7-tetrazocine)
76-44-8 Heptachlorc 0.002a
1024-57-3 Heptachlor epoxidec 0.001a
77-47-4 Hexachlorocyclopentadiene 0.5e
193-39-5 Indeno(1,2,3-c,d)pyrened 0.0012a
98-82-8 Isopropylbenzene (cumene)c 1.9a
93-65-2 MCPP (mecoprop) 0.1b
1634-04-4 MTBE (methyl 0.5e
tertiary-butyl ether)
72-43-5 Methoxychlor 0.2a
90-12-0 1-Methylnaphthalene 1.35a
91-57-6 2-Methylnaphthalene 0.075a
95-48-7 2-Methylphenol (o-cresol) 0.19b
91-20-3 Naphthalene 0.39a
98-95-3 Nitrobenzene 0.0077b
1336-36-3 PCBs (polychlorinated 0.0025a
biphenyls as decachloro-
biphenyl)c
375-73-5 PFBS 0.002b
(perfluorobutanesulfonic acid)
355-46-4 PFHxS 0.000010b
(perfluorohexanesulfonic acid)
375-95-1 PFNA (perfluorononanoic acid) 0.000010b
335-67-1 PFOA (perfluorooctanoic acid)c 0.000004b
1763-23-1 PFOS 0.000004b
(perfluorooctanesulfonic acid)c
87-86-5 Pentachlorophenol 0.005a
108-95-2 Phenol 0.1ii
1918-02-1 Picloram 5.0e
129-00-0 Pyrene 0.6a
121-82-4 RDX (hexahydro-l,3,5-trinitro- 0.062b
l,3,5-trianzine)
122-34-9 Simazine 0.04e
100-42-5 Styrene 0.5a
118-96-7 TNT (2,4,6-trinitrotoluene) 0.039a
93-72-1 2,4,5-TP (silvex) 0.25a
127-18-4 Tetrachloroethylenec 0.025a
108-88-3 Toluene 2.5f
8001-35-2 Toxaphenec 0.015a
120-82-1 1,2,4-Trichlorobenzene 0.7e
71-55-6 1,1,1-Trichloroethane 1a
79-00-5 1,1,2-Trichloroethane 0.05e
79-01-6 Trichloroethylened 0.025a
75-69-4 Trichlorofluoromethane 6a
99-35-4 1,3,5-Trinitrobenzene 2.3a
75-01-4 Vinyl chlorided 0.01a
1330-20-7 Xylenes 10b
Constituent Name and Groundwater Quality Standard Notations
a A treatment factor of 5 is applied to the Class I groundwater quality standard. The constituent’s treatment efficiency is based on the effectiveness to treat the constituent in the groundwater at an 80% removal efficiency rate for the constituent.
b The Agency’s treatment efficiency determination demonstrates a treatment factor is not applicable for the constituent. The standard is equal to the Class I groundwater quality standard.
c The constituent meets the definition of a "carcinogen" in Section 620.110.
d The constituent meets the definition of a "mutagen" in Section 620.110.
e A treatment factor of 10 is applied to the Class I groundwater quality standard. The constituent’s treatment efficiency is based on the effectiveness to treat the constituent in the groundwater at a 90% removal efficiency rate for the constituent.
f A treatment factor of 2.5 is applied to the Class I groundwater quality standard. The constituent’s treatment efficiency is based on the effectiveness to treat the constituent in the groundwater at a 60% removal efficiency rate for the constituent.
g A treatment factor of 3 is applied to the Class I groundwater quality standard. The constituent’s treatment efficiency is based on the effectiveness to treat the constituent in the groundwater at a 65% removal efficiency rate for the constituent.
h A treatment factor of 1.5 is applied to the Class I groundwater quality standard. The constituent’s treatment efficiency is based on the effectiveness to treat the constituent in the groundwater at a 30% removal efficiency rate for the constituent.
i The standard is based on 35 Ill. Adm. Code 302.208.
2) The standards for pesticide chemical constituents specified in subsection (b)(1) do not apply to groundwater within 10 feet of the land surface if the concentrations of the constituents result from applying pesticides in a manner consistent with the Federal Insecticide, Fungicide, and Rodenticide Act (7 U.S.C. 136 et seq.) and the Illinois Pesticide Act [415 ILCS 60].
c) Complex Organic Chemical Mixtures
1) Concentrations of the following organic chemical constituents must not be exceeded in Class II groundwater:
CASRN Constituent Standard
(mg/L)
71-43-2 Benzenea 0.025b
Total BETX 13.525c
Constituent Name and Groundwater Quality Standard Notations
a The constituent meets the definition of a "carcinogen" in Section 620.110.
b A treatment factor of 5 is applied to the Class I groundwater quality standard. The constituent’s treatment efficiency is based on the effectiveness to treat the constituent in the groundwater at an 80% removal efficiency rate for the constituent.
c The standard is the total combined Class II standard of benzene, ethylbenzene, toluene, and xylenes.
2) Atrazine and Metabolites
Concentration of the following chemical constituents must not be exceeded in Class II groundwater.
CASRN Constituent Standard
(mg/L)
1912-24-9 Atrazine 0.015a
Total Atrazine and Metabolites 0.015
6190-65-4 DEA (desethyl-atrazine)
1007-28-9 DIA (desisopropyl-atrazine)
3397-62-4 DACT (diaminochlorotriazine)
Constituent Name and Groundwater Quality Standard Notations:
a A treatment factor of 5 is applied to the Class I groundwater quality standard. The constituent’s treatment efficiency is based on the effectiveness to treat the constituent in the groundwater at an 80% removal efficiency rate for the constituent.
d) pH
Except due to natural causes, a pH range of 6.5 - 9.0 units must not be exceeded in Class II groundwater.
e) No facility that is subject to 35 Ill. Adm. Code 811 or 814 must comply with any requirement or standard of those rules to the extent it incorporates or is otherwise based on any of the following constituents or their standards under this Section:
CASRN Constituent
13252-13-6 HFPO-DA
(hexafluoropropylene oxide
dimer acid GenX)
375-73-5 PFBS
(perfluorobutanesulfonic acid)
355-46-4 PFHxS
(perfluorohexanesulfonic acid)
375-95-1 PFNA (perfluorononanoic acid)
335-67-1 PFOA (perfluorooctanoic acid)
1763-23-1 PFOS
(perfluorooctanesulfonic acid)
(Source: Amended at 49 Ill. Reg. 4488, effective March 28, 2025)
Section 620.430 Groundwater Quality Standards for Class III: Special Resource Groundwater
Except due to natural causes, concentrations of inorganic and organic chemical constituents and ranges of pH must not exceed the standards specified in Section 620.410. This prohibition does not apply to:
a) Chemical constituents for which the Board has adopted standards under Section 620.260; or
b) Class III Special Resource Groundwater established under Section 620.230(b) and depicted in the Environmental Register, but only at the dedicated nature preserves identified in this subsection (b), and only for the conditions at those preserves for which standards are specified in this subsection (b).
1) The following standards apply for Pautler Cave Nature Preserve and Stemler Cave Nature Preserve (Environmental Register, May 2005, No. 611), Fogelpole Cave Nature Preserve (Environmental Register, May 2003, No. 587), and Armin Krueger Speleological Nature Preserve (Environmental Register, December 2009, No. 666):
Chloride 20 mg/L
pH range of 7.0-9.0 Standard Units
2) The following standard applies for Cotton Creek Marsh Nature Preserve and Spring Grove Fen Nature Preserve (Environmental Register, July 2012, No.697):
Chloride 45 mg/L
(Source: Amended at 49 Ill. Reg. 4488, effective March 28, 2025)
Section 620.440 Groundwater Quality Standards for Class IV: Other Groundwater
a) Except as provided in subsection (b), (c), (d), or (e), Class IV: Other Groundwater standards are equal to the existing concentrations of constituents in groundwater.
b) For groundwater within a zone of attenuation as defined in 35 Ill. Adm. Code 810.103 and determined in compliance with 35 Ill. Adm. Code 811.320(c), the standards specified in Section 620.420 must not be exceeded. This prohibition does not apply to any concentrations of contaminants within leachate released from a permitted unit.
c) For groundwater within a previously mined area, the standards specified in Section 620.420 must not be exceeded, except the standards are the existing concentrations for TDS, chloride, iron, manganese, sulfates, pH, 1,3-dinitrobenzene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), nitrobenzene, RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine royal), 1,3,5-trinitrobenzene, and TNT (2,4,6-trinitrotoluene).
d) For groundwater regulated under Part 845, the groundwater protection standard (GWPS) under Section 845.600 must not be exceeded for any constituent with a GWPS under Section 845.600. For any constituent that does not have a GWPS under Section 845.600, the groundwater quality standards (GWQS) of Sections 620.410, 620.420, 620.430 or 620.440(b) and (c) apply.
e) Nothing in this Section limits underground injection in compliance with an underground injection control program administered by the Agency under the Act, by the Department of Natural Resources, Office of Oil and Gas Resource Management under the Illinois Oil and Gas Act [225 ILCS 725], or by USEPA under the federal UIC regulations [40 CFR 144].
(Source: Amended at 49 Ill. Reg. 4488, effective March 28, 2025)
Section 620.450 Alternative Groundwater Quality Standards
a) Groundwater Quality Restoration Standards
1) Subsections (a)(3) and (a)(4)(B) apply to all released chemical constituents in groundwater within a groundwater management zone (GMZ) that are the subject of the GMZ approved under Section 620.250(c)(2).
2) Subsection (a)(4)(A) applies to all released chemical constituents in groundwater within a three-dimensional region formerly encompassed by a GMZ that were the subject of the GMZ approved under Section 620.250(c)(2).
3) Before the Agency issues a written determination approving the demonstration of the site owner or operator under Section 620.250(d)(1) or (d)(2), none of the standards specified in Section 620.410, 620.420, 620.430, or 620.440 apply to any released chemical constituent if the owner or operator performs and complies with the schedule for all parts of the GMZ.
4) After the Agency issues a written determination approving the demonstration of the site owner or operator under Section 620.250(d)(1) or (d)(2), the standard for each released chemical constituent is:
A) The standard specified in Section 620.410, 620.420, 620.430, or 620.440 if the concentration of the constituent, as determined by groundwater monitoring, is less than or equal to the standard for the applicable class of groundwater specified in one of those Sections; or
B) The concentration of the constituent, as determined by groundwater monitoring, if the concentration exceeds the standard for the otherwise applicable class of groundwater specified in Section 620.410, 620.420, 620.430, or 620.440 and:
i) To the extent practicable, the exceedance has been minimized and beneficial use, as appropriate for the otherwise applicable class of groundwater, has been returned; and
ii) Any threat to public health or the environment has been minimized.
5) The Agency must develop and maintain a list of all concentrations derived under subsection (a)(4)(B). For each concentration, the list must identify the location of the corresponding GMZ. On its website (
https://epa.illinois.gov
), the Agency must post the list and, at least semi-annually, update it. In addition, at least annually, the Agency must submit the list to the Board for publication in the Environmental Register.
b) Coal Reclamation Groundwater Quality Standards
1) Any inorganic chemical constituent or pH in groundwater, within an underground coal mine, or within the cumulative impact area of groundwater for which the hydrologic balance has been disturbed from a permitted coal mine area under the Surface Coal Mining Land Conservation and Reclamation Act [225 ILCS 720] and 62 Ill. Adm. Code 1700 through 1850, is subject to this subsection (b).
2) Before completion of reclamation at a coal mine, the standards specified in Sections 620.410(a) and (e), 620.420(a) and (e), 620.430, and 620.440 do not apply to inorganic constituents and pH.
3) After completion of reclamation at a coal mine, the standards specified in Sections 620.410(a) and (e), 620.420(a), 620.430, and 620.440 apply to inorganic constituents and pH, except:
A) The concentration of total dissolved solids (TDS) must not exceed:
i) The post-reclamation concentration of TDS or 3000 mg/L, whichever is less, for groundwater within the permitted area; or
ii) The post-reclamation concentration of TDS or 5000 mg/L, whichever is less, for groundwater in underground coal mines and in permitted areas reclaimed after surface coal mining if the Illinois Office of Mines and Minerals, Department of Natural Resources and the Agency have determined that no significant resource groundwater existed before mining (62 Ill. Adm. Code 1780.21(f) and (g)).
B) The concentration of chloride, iron, manganese, and sulfate, must not exceed the post-reclamation concentration within the permitted area.
C) pH must not exceed the post-reclamation concentration within the permitted area in Class I: Potable Resource Groundwater described in Section 620.210(a)(4).
D) The concentration of 1,3-dinitrobenzene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), nitrobenzene, RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), 1,3,5-trinitrobenzene, and TNT (2,4,6-trinitrotoluene) must not exceed the post-reclamation concentration within the permitted area.
4) A refuse disposal area (not contained within the area from which overburden has been removed) is subject to the inorganic chemical constituent and pH requirements of:
A) 35 Ill. Adm. Code 302.Subparts B and C, except due to natural causes, for an area that began operating after February 1, 1983, and before November 25, 1991, if the groundwater is a present or potential source of water for public or food processing;
B) Section 620.440(c) for an area that began operating before February 1, 1983, and has remained in continuous operation since that date; or
C) Subpart D for an area that begins operating on or after November 25, 1991.
5) For a refuse disposal area (not contained within the area from which overburden has been removed) that began operating before February 1, 1983, and is modified after that date to include additional area, this subsection (b) applies to the area that complies with subsection (b)(4)(C) and the following applies to the additional area:
A) 35 Ill. Adm. Code 302.Subparts B and C, except due to natural causes, for an additional refuse disposal area that began operating after February 1, 1983, and before November 25, 1991, if the groundwater is a present or potential source of water for public or food processing; and
B) Subpart D for an additional area that began operating on or after November 25, 1991.
6) A coal preparation plant (not in an area from which overburden has been removed) that contains slurry material, sludge, or other precipitated process material is subject to the inorganic chemical constituent and pH requirements of:
A) 35 Ill. Adm. Code 302.Subparts B and C, except due to natural causes, for a plant that began operating after February 1, 1983, and before November 25, 1991, if the groundwater is a present or potential source of water for public or food processing;
B) Section 620.440(c) for a plant that began operating before February 1, 1983, and has remained in continuous operation since that date; or
C) Subpart D for a plant that begins operating on or after November 25, 1991.
7) For a coal preparation plant (not in an area from which overburden has been removed) that contains slurry material, sludge, or other precipitated process material, began operating before February 1, 1983, and is modified after that date to include additional area, this subsection (b) applies to the area that complies with subsection (b)(6)(C) and the following applies to the additional area:
A) 35 Ill. Adm. Code 302.Subparts B and C, except due to natural causes, for an additional area that began operating after February 1, 1983, and before November 25, 1991, if the groundwater is a present or potential source of water for public or food processing; and
B) Subpart D for an additional area began operating on or after November 25, 1991.
c) Groundwater Quality Standards for Specified Groundwater Subject to a No Further Remediation Letter under the Site Remediation Program (35 Ill. Adm. Code 740). While a No Further Remediation Letter is in effect for a region formerly encompassed by a GMZ established under 35 Ill. Adm. Code 740.530, the applicable groundwater quality standards for the specified "contaminants of concern", as defined in 35 Ill. Adm. Code 740.120, within that area are the groundwater objectives achieved as documented in the approved Remedial Action Completion Report.
(Source: Amended at 49 Ill. Reg. 4488, effective March 28, 2025)
| HTTAC | = | Human Threshold Toxicant Advisory Concentration in milligrams per liter (mg/L); |
| RSC | = | Relative contribution of the amount of the exposure to a chemical via drinking water when compared to the total exposure to that chemical from all sources. Valid chemical-specific data must be used if available. If valid chemical-specific data are not available, a value of 20% (= 0.20) must be used; |
| ADE | = | Acceptable Daily Exposure of substance in milligrams per day (mg/d) as determined under subsection (b); and |
| W | = | Per capita daily water consumption for a child (0-6 years of age), equal to 0.78 liters per day (L/d). |
| HI | =
|
Hazard Index, unitless. |
| [A], [B], [I] | =
|
Concentration of each similar-acting substance in groundwater in milligrams per liter (mg/L). |
| ALA, ALB, ALI | =
|
The acceptable level of each similar-acting substance in the mixture in milligrams per liter (mg/L). |
| Note 1. | Parts I, II, and III of this Appendix D specify the information required for the GMZ application that the owner or operator submits to the Agency. See 35 Ill. Adm. Code 620.250(b). Part IV of this Appendix D specifies the information required for the corrective action completion certification that the owner or operator submits to the Agency. See 35 Ill. Adm. Code 620.250(d). The owner or operator is neither required to use the form specified in Part I, II, III, or IV of this Appendix D nor precluded from including information in addition to that required by this Appendix D. See 35 Ill. Adm. Code 620.250(b)(2), (b)(3), (d).
|
| Note 2. | The issuance of a permit by the Agency's Division of Air Pollution Control or Water Pollution Control for a treatment system does not imply that the Agency has approved any corrective action process.
|
| Note 3. | Parts I, II, and III of this Appendix D are not for use in establishing a GMZ under the Site Remediation Program (35 Ill. Adm. Code 740). See 35 Ill. Adm. Code 620.250(h).
|
| Note 4.
Note 5. |
If the GMZ would extend off-site, the GMZ application must include each off-site property owner's written permission to the establishment of the GMZ on its property. If effectively implementing the off-site portion of the GMZ requires accessing an off-site property, the GMZ application must also include the off-site property owner's written permission for that access. If the applicable written permission or permissions from an off-site property owner are not obtained—whether permission to establish the GMZ off-site, access the off-site property, or both-- the GMZ will not include that off-site property. See 35 Ill. Adm. Code 620.250(b)(1).
If a response to any item in this Appendix D requires additional explanation or clarification, provide it in an attachment to the submittal. |
| Part I; | Facility Information |
| Facility Name |
| Facility Address |
| County |
| Standard Industrial Code (SIC) |
| YES | NO
|
||
| Landfill | |||
| Surface Impoundment | |||
| Land Treatment | |||
| Spray Irrigation | |||
| Waste Pile | |||
| Incinerator | |||
| Storage Tank (above ground) | |||
| Storage Tank (underground) | |||
| Container Storage Area | |||
| Injection Well | |||
| Water Treatment Units | |||
| Septic Tanks | |||
| French Drains | |||
| Transfer Station |
| Other Units (describe) |
| Facility Name | Signature of Owner/Operator |
| Location of Facility | Name of Owner/Operator |
| EPA Identification Number | Date |
Chemical Description
|
Chemical Abstract No.
|
|
| Facility Name | Signature of Owner/Operator |
| Location of Facility | Name of Owner/Operator |
| EPA Identification Number | Date |
| Facility Name | Signature of Owner/Operator |
| Location of Facility | Name of Owner/Operator |
| EPA Identification Number | Date |
| Facility Name |
| Facility Address | |
| County | |
| Standard Industrial Code (SIC) |
| Date |
Chemical Name
|
Chemical Abstract No.
|
Concentration (mg/L)
|
||
| Facility Name | Signature of Owner/Operator |
| Location of Facility | Name of Owner/Operator |
| EPA Identification Number | Date |
Cholinesterase Inhibition
116-06-3 Aldicarb
1563-66-2 Carbofuran
Circulatory System
15972-60-8 Alachlor
7440-36-0 Antimony
1912-24-9 Atrazine
71-43-2 Benzene
94-75-7 2,4-D (2,4-dichlorophenoxy acetic acid)
121-14-2 2,4-Dinitrotoluene
206-44-0 Fluoranthene
86-73-7 Fluorene
98-95-3 Nitrobenzene
122-34-9 Simazine
100-42-5 Styrene
79-01-6 Trichloroethylene
99-35-4 1,3,5-Trinitrobenzene
7440-66-6 Zinc
Decreased Body Weight
75-71-8 Dichlorodifluoromethane
84-66-2 Diethyl phthalate
95-48-7 2-Methylphenol (o-cresol)
91-20-3 Naphthalane
7440-02-0 Nickel
108-95-2 Phenol
122-34-9 Simazine
71-55-6 1,1,1-Trichloroethane
1330-20-7 Xylenes
Developmental
7429-90-5 Aluminum
50-32-8 Benzo(a)pyrene
7440-42-8 Boron
78-93-3 2-Butanone (methyl ethyl ketone)
75-15-0 Carbon disulfide
78-87-5 1,2-Dichloropropane
84-66-2 Diethyl phthalate
88-85-7 Dinoseb
7439-93-2 Lithium
375-73-5 PFBS (perfluorobutanesulfonic acid)
375-95-1 PFNA (perfluorononanoic acid)
1763-23-1 PFOS (perfluorooctanesulfonic acid)
335-67-1 PFOA (perfluorooctanoic acid)
Endocrine System
106-93-4 Ethylene dibromide (1,2-dibromoethane)
120-82-1 1,2,4-Trichlorobenzene
Gastrointestinal System
7440-41-7 Beryllium
7440-50-8 Copper
145-73-3 Endothall
77-47-4 Hexachlorocyclopentadiene
7439-89-6 Iron
1634-04-4 MTBE (methyl tertiary-butyl-ether)
Immune System
156-60-5 trans-1,2-Dichloroethylene
58-89-9 gamma-HCH (gamma-hexachlorocyclohexane, lindane)
7487-94-7 Mercury (mercuric chloride)
76-44-8 Heptachlor
355-46-4 PFHxS (perfluorohexanesulfonic acid)
375-95-1 PFNA (perfluorononanoic acid)
1763-23-1 PFOS (perfluorooctanesulfonic acid)
335-67-1 PFOA (perfluorooctanoic acid)
Kidney
7440-39-3 Barium
7440-43-9 Cadmium
94-75-7 2,4-D (2,4-dichlorophenoxy acetic acid)
75-99-0 Dalapon
75-34-3 1,1-Dichloroethane
107-06-2 1,2-Dichloroethane
156-59-2 cis-1,2-Dichloroethylene
123-91-1 1,4-Dioxane (p-dioxane)
206-44-0 Fluoranthene
98-82-8 Isopropylbenzene (cumene)
7439-93-2 Lithium
93-65-2 MCPP (mecoprop)
7487-94-7 Mercury (mercuric chloride)
7439-98-7 Molybdenum
129-00-0 Pyrene
108-88-3 Toluene
7440-62-2 Vanadium
Liver
83-32-9 Acenaphthene
319-84-6 alpha-BHC (alpha-benzene hexachloride)
56-23-5 Carbon Tetrachloride
12789-03-6 Chlordane
108-90-7 Chlorobenzene
67-66-3 Chloroform
94-75-7 2,4-D (2,4-dichlorophenoxy acetic acid)
106-46-7 p-Dichlorobenzene (1,4-dichlorobenzene)
75-35-4 1,1-Dichloroethylene
75-09-2 Dichloromethane (methylene chloride)
117-81-7 Di(2-ethylhexyl)phthalate
121-14-2 2,4-Dinitrotoluene
123-91-1 1,4-Dioxane (p-dioxane)
72-20-8 Endrin
100-41-4 Ethylbenzene
106-93-4 Ethylene dibromide (1,2-dibromoethane)
206-44-0 Fluoranthene
13252-13-6 HFPO-DA (hexafluoropropylene oxide dimer acid, GenX)
2691-41-0 HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine)
1024-57-3 Heptachlor Epoxide
1634-04-4 MTBE (methyl tertiary-butyl ether)
87-86-5 Pentachlorophenol
1918-02-1 Picloram
100-42-5 Styrene
118-96-7 TNT (2,4,6-trinitrotoluene)
93-72-1 2,4,5-TP (silvex)
75-01-4 Vinyl Chloride
Lungs
90-12-0 1-Methylnaphthalene
91-57-6 2-Methylnaphthalene
Mortality
84-74-2 Di-n-butyl phthalate
1330-20-7 Xylenes
Nervous System
67-64-1 Acetone
121-14-2 2,4-Dinitrotoluene
72-20-8 Endrin
7439-93-2 Lithium
7439-96-5 Manganese
95-48-7 2-Methylphenol (o-cresol)
121-82-4 RDX (hexahydro-1,3,5-trinitro- l,3,5-triazine)
127-18-4 Tetrachloroethylene
Reproductive System
1912-24-9 Atrazine
96-12-8 1,2-Dibromo-3-chloropropane
1563-66-2 Carbofuran
75-15-0 Carbon disulfide
143-33-9 Cyanide
1918-00-9 Dicamba
106-93-4 Ethylene dibromide (1,2-dibromoethane)
7439-93-2 Lithium
72-43-5 Methoxychlor
Skin
7440-38-2 Arsenic
7440-22-4 Silver
7440-28-0 Thallium
Spleen
99-65-0 1,3-Dinitrobenzene
606-20-2 2,6-Dinitrotoluene
99-35-4 1,3,5-Trinitrobenzene
Thyroid
7440-48-4 Cobalt
14797-73-0 Perchlorate
355-46-4 PFHxS (perfluorohexanesulfonic acid)
375-73-5 PFBS (perfluorobutanesulfonic acid)
8001-35-2 Toxaphene
Whole Body
120-12-7 Anthracene
7440-36-0 Antimony
65-85-0 Benzoic Acid
95-50-1 o-Dichlorobenzene (1,2-dichlorobenzene)
206-44-0 Fluoranthene
7782-49-2 Selenium
79-00-5 1,1,2-Trichloroethane
75-69-4 Trichlorofluoromethane
(Source: Added at 49 Ill. Reg. 4488, effective March 28, 2025)
Section 620.APPENDIX E Similar-Acting Substances
620.TABLE B Similar-Acting Carcinogenic Constituents
Circulatory System
71-43-2 Benzene
107-06-2 1,2-Dichloroethane
106-93-4 Ethylene dibromide (1,2-dibromoethane)
Gastrointestinal System
56-55-3 Benzo(a)anthracene
205-99-2 Benzo(b)fluoranthene
207-08-9 Benzo(k)fluoranthene
50-32-8 Benzo(a)pyrene
218-01-9 Chrysene
53-70-3 Dibenzo(a,h)anthracene
106-93-4 Ethylene dibromide (1,2-dibromoethane)
193-39-5 Indeno(1,2,3-c,d)pyrene
Kidney
67-66-3 Chloroform
96-12-8 1,2-Dibromo-3-chloropropane (dibromochloropropane)
121-14-2 2,4-Dinitrotoluene
606-20-0 2,6-Dinitrotoluene
100-41-4 Ethylbenzene
79-01-6 Trichloroethylene
Liver
319-84-6 alpha-BHC (alpha-benzene hexachloride)
56-23-5 Carbon tetrachloride
12789-03-6 Chlordane
106-46-7 p-Dichlorobenzene (1,4-dichlorobenzene)
75-09-2 Dichloromethane (methylene chloride)
78-87-5 1,2-Dichloropropane
117-81-7 Di(2-ethylhexyl)phthalate
121-14-2 2,4-Dinitrotoluene
606-20-0 2,6-Dinitrotoluene
123-91-1 1,4-Dioxane (p-dioxane)
58-89-9 gamma-HCH (gamma -hexachlorocyclohexane, lindane)
76-44-8 Heptachlor
1024-57-3 Heptachlor epoxide
1336-36-3 PCBs (polychlorinated biphenyls as decachloro-biphenyl)
335-67-1 PFOA (perfluorooctanoic acid)
87-86-5 Pentachlorophenol
127-18-4 Tetrachloroethylene
8001-35-2 Toxaphene
79-01-6 Trichloroethylene
75-01-4 Vinyl Chloride
Mammary Gland
121-14-2 2,4-Dinitrotoluene
606-20-0 2,6-Dinitrotoluene
(Source: Added at 49 Ill. Reg. 4488, effective March 28, 2025)