National Pretreatment Program Regulatory History

EPA originally published the general pretreatment regulations in 1978. These regulations have been updated many times since then, with substantial amendments in 2005 as the “Streamlining Rule” and minor edits with the NPDES Electronic Reporting Rule. The timeline below highlights key pretreatment regulatory changes and the significant events or publications that brought about those changes. Related documents and materials are also provided.

Current Regulatory Activities

EPA develops and publishes new regulations and periodically updates existing regulations. There are current rulemaking activities expected to result in changes to the general pretreatment regulations at 40 CFR Part 403. The following will affect the implementation of the national pretreatment program:

Regulatory Timeline
Regulatory Activity	Related Materials	Date	Summary	Topic(s)
Availability of and Procedures for Removal Credits	70 FR 60199 – 60202(4 pp, 173 K, About PDF)	10/14/2005	EPA sought comment on two issues concerning the removal credits provisions in the General Pretreatment Regulations	Requested comments on whether to amend the list of pollutants for which removal credits are available to add certain pollutants Comments were closed on December 13, 2005 and no rulemaking activities were initiated for these issues
Streamlining the General Pretreatment Regulations for Existing and New Sources of Pollution (Streamlining Rule)	Streamlining Rule Fact Sheets	2006 - 2009	Fact sheet series outlining the changes made to the pretreatment program at 40 CFR Part 403 under the Pretreatment Streamlining Rule	1: Summary of Changes Made Under the Streamlining Rule 2: Required Changes 3: Equivalent Mass Limits for Concentration Limits 4: Equivalent Concentration-Based Limits for Flow-Based Standards 5: New Classifications for Categorical Industrial Users 6: Optional Sampling Waiver for Pollutants Not Present 7: Best Management Practices 8: Slug Control Plans 9: General Control Mechanisms Option
	70 FR 60134-60198(65 pp, 463 K, About PDF)	10/14/2005	Changes to the General Pretreatment Regulations that address restrictions on and oversight of industrial users who introduce pollutants into publicly owned treatment works (POTWs) and modified certain program requirements to be consistent with National Pollutant Discharge Elimination System (NPDES) requirements	Authorized representative/duly-authorized employee Best management practices Concentration-based categorical pretreatment standards expressed as equivalent mass limits Equivalent concentration limits in lieu of mass limits for certain categories of categorical industrial users (CIUs) Flexibility in the use of certain sampling techniques General control mechanisms Middle-tier CIUs Non-significant CIUs Notification requirements Reduced sampling for categorically regulated pollutants neither present nor expected to be present Removal credits reference update Representative samples Significant noncompliance (SNC) criteria Slug control requirements
	64 FR 39564 - 39605(42 pp, 457 K, About PDF)	7/22/1999
Project eXcellence and Leadership for Communities (Project XL)	63 FR 34170 - 34176(7 pp, 177 K, About PDF)	6/23/1998	Solicitation of local pilot pretreatment program proposals under Project XL	Invited POTWs to propose alternative environmental performance-based pretreatment programs Four POTWs conducted five experimental water regulatory projects None of the pilot projects demonstrated pretreatment program alternatives that could be implemented at the national level
	66 FR 50334-40	10/3/2021
	65 FR 59738-48	10/6/2000
Streamlined Procedures for Modifying Approved Publicly Owned Treatment Works Pretreatment Programs	62 FR 38406-38415(10 pp, 155 K, About PDF)	7/17/1997		Revised the procedures for modifying approved POTW Pretreatment Programs incorporated into NPDES permits issued to POTWs Revisions designed to reduce the administrative burden and cost associated with maintaining approved pretreatment programs without affecting environmental protection
	61 FR 39804-39810(7 pp, 137 K, About PDF)	7/30/1996
Standards for the Disposal of Sewage Sludge	60 FR 54764-54770(7 pp, 215 K, About PDF)	10/25/1995	EPA reconsidered issues remanded by the U.S. Court of Appeals for additional justification or modification	EPA amended 40 CFR Part 503 to delete the land application pollutant limits for chromium and to change the land application pollutant concentration limit for selenium EPA also amended the list of pollutants (in Appendix G of 40 CFR Part 403) for which a removal credit may be available
	58 FR 9248 – 9404	2/19/1993		Leather Industries of America, Inc., (3/5/1993) and City of Pueblo, CO (6/17/1993) file petitions challenging the proposed rule, which are consolidated as the court case Leather Industries of America, Inc. v. Environmental Protection Agency, 40 F.3d 392, D.C. Cir., 1994 (11/15/1994) Adds Appendix G to the Part 403 general pretreatment regulations Appendix G—Section I lists the pollutants regulated in Part 503 and eligible for removal credit authorization Appendix G–Section II lists additional pollutants that are eligible for a removal credit if the concentration of the pollutant in sewage sludge does not exceed a prescribed concentration Appendix G—Section II lists the pollutants that EPA evaluated and opted not to regulate during development of the Part 503 regulation Establishes 40 CFR Part 503 EPA promulgated regulation to protect public health and the environment from the reasonably anticipated adverse effects of certain pollutants in sewage sludge Established requirements for the following final uses or disposal of sewage sludge: 1) land application either to condition the soil or to fertilize crops grown in the soil; 2) final disposal on the land; and 3) incineration
	54 FR 5746 – 5902	2/6/1989
Pretreatment Program and Domestic Sewage Exclusion Rulemaking (“Hazardous Solid Waste Amendments” [HSWA])	55 FR 30082 – 31033 Final Rule	7/24/1990	Regulations to enhance control of toxic pollutants and hazardous waste discharges to POTWs	Expanded specific prohibitions on discharges into POTWs; established requirements regarding significant industrial user slug discharge control plans and POTW enforcement response plans; and strengthened and revised program implementation definitions and procedures
	53 FR 47632 – 45656	11/23/1988	Proposal to Implement the Recommendations of the Domestic Sewage Study (DSS)
	52 FR 23477 – 23485	6/22/1987	Response to comments on the Advanced Notice of Proposed Rulemaking	Agency summarized the comments received during three public meetings on DSS recommendations ANPR Response to comments
	51 FR 30166 – 30175	8/22/1986	Preliminary Approaches to Implementing the Recommendations of the DSS	Based on DSS findings Proposal to improve methods for controlling hazardous waste discharges to POTWs under the NPDES and general pretreatment programs.
	Report to Congress on the Discharge of Hazardous Wastes to Publicly Owned Treatment Works (Domestic Sewage Study)	2/7/1986	Response to the HSWA requirements to prepare a report to Congress	Contained information on 160,000 waste dischargers from 47 industrial categories and the residential sector Provided information on the effectiveness of existing government controls for wastewater discharges, especially federal and local pretreatment programs and categorical pretreatment standards
	Solid Waste Disposal Act	1984	Congress enacts the Solid Waste Disposal Act	Section 3018(a) Excluded coverage of solid and dissolved wastes in domestic sewage, meaning such wastes did not have to meet RCRA standards for hazardous waste treatment, storage, or disposal Required EPA to prepare a report to Congress on the extent to which excluded wastes pass through POTWs
Part 403 General Pretreatment Regulations for Existing and New Sources	52 FR 1586-1600 (pdf) (4.95 MB) (begins on page 1585)	1/14/1987	On February 10, 1984, EPA suspended the provisions defining the terms “interference” and “pass through” in response to the decision of the US Court of Appeals for the Third Circuit in National Association of Metal Finishers v. EPA, 719 F.2d624 (3rd Cir. 1983) (NAMF).	Interference and Pass through
	50 FR 25526-25529 (pdf) (22.38 MB) (begins on page 22525)	6/19/1985	Today, EPA is issuing a final rule defining “interference” and “pass through” to replace the previously suspended provisions of the pretreatment regulations. Today’s rule also established two affirmative defenses to violations of the general prohibitions against interference and pass through in §403.5(a) and of the specific prohibitions in §403.5(b)(3), (4), and (5).	Interference and Pass through
Pretreatment Implementation Review Task Force (PIRT)	53 FR 40561 – 40616	10/17/1988	General Pretreatment Regulations for Existing and New Sources (PIRT Proposed and Final Rules)	Changes to 40 CFR Parts 122 and 403 Response to PIRT recommendations Revisions included changes to local limits requirements, enforcement remedies, control authority and state program approvals, as well as industrial user and control authority monitoring and reporting requirements
	51 FR 21454 – 21482	6/12/1986
	Pretreatment Review Task Force: Final Report to the Administrator	1/3/1985	Task Force studied programs and recommended program improvements	Recommended ways to address day-to-day problems faced by POTWs, states, and industries in implementing the National Pretreatment Program Included suggestions for simplifying and clarifying aspects of the program, on enforcement procedures, on the need for program resources, on the roles and relationships between program oversight authorities, and for regulatory updates
Amendments to the General Pretreatment Regulations	47 FR 42688 – 42689	9/28/1982	EPA reinstated the January 1981 amendments	After Natural Resources Defense Council (NRDC) v. EPA (No. 81-2068) (7/8/1982) in which NRDC challenged EPA over the Agency’s deferral of the amendments to the General Pretreatment Regulations without having first given public notice Court held that EPA’s suspension violated the Administrative Procedure Act Court ordered EPA to reinstate all pretreatment amendments retroactive to March 30, 1981
	46 FR 19936	4/2/1981	EPA indefinitely postponed the 1981 Amendments' effective date
	46 FR 11972	2/2/1981	Deferral of Amendments to the General Pretreatment Regulations	Presidential memorandum temporarily deferring amendment to March 30, 1981
	46 FR 9404 – 9460	1/28/1981		Proposed changes to definitions, general prohibitions, determination of industrial subcategories, removal allowances, and implementation issues for local pretreatment programs Scheduled to take effect on March 13, 1981
	44 FR 62260 – 62275	10/29/1979
Part 403 General Pretreatment Regulations for Existing and New Sources of Pollution	43 FR 27736 - 27773	6/26/1978	EPA response to environmental groups (NRDC, Environmental Defense Fund (EDF), and Citizens For A Better Environment) bringing suit against EPA and the resulting consent decree	In the 1976, NRDC vs. Train Consent Decree (8ERC 2120, D.D.C. 1976), 21 industries are under consideration by EPA for national pretreatment standards pursuant to a settlement agreement between EPA and environmental groups filed in the U.S. District Court for the District of Columbia Promulgation of General Pretreatment Regulations at 40 CFR Part 403, replacing the 40 CFR Part 128 requirements EPA agreed to regulate the discharge of 65 categories of pollutants comprising the 126 priority pollutants from 21 industrial categories
	42 FR 6476 – 6502	2/2/1977
Pollutants in Publicly Owned Treatment Works Pretreatment Standards; 40 CFR Part 128 Pretreatment Standards	38 FR 30982 Final Rule	11/8/1973	Original pretreatment regulations	Established 40 CFR Part 128 Defined: joint treatment works, major contributing industry; pretreatment First proposal of pretreatment standards, prohibited discharges, pretreatment of compatible and incompatible pollutants, and timeline for compliance with pretreatment standards
	38 FR 19236 -19237 Proposed Rule	7/19/1973	Original pretreatment regulations

National Pretreatment Program Regulatory History

Current Regulatory Activities

National Pollutant Discharge Elimination System (NPDES)