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  1. Home
  2. National Pollutant Discharge Elimination System (NPDES)

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pubs from w3

TitleLinkDescriptionURL
Protocol for Determining Economic Achievability for NPDES Permits Protocol for Determining Economic Achievability for NPDES Permits (pdf) (189.6 KB) Guidance for determining economic achievability when establishing best available technology economically achievable (BAT) on a case-by-case basis in NPDES Permits.https://www.epa.gov/system/files/documents/2026-04/1982-protocol-economic-achievability-npdes.pdf
Work Book for Determining Economic Achievability for National Pollution Discharge Elimination System Permits Work Book for Determining Economic Achievability for National Pollution Discharge Elimination System Permits (pdf) (1.25 MB) Worksheets for determining economic achievability when establishing best available technology economically achievable (BAT) on a case-by-case basis in NPDES permits.https://www.epa.gov/system/files/documents/2026-04/1982-workbook-economic-achievability-npdes.pdf
Toxicity Testing Requirements in Municipal Permits Toxicity Testing Requirements in Municipal Permits (pdf) (298.63 KB) Guidance urging inclusion of whole effluent toxicity (WET) testing in permits for POTWs.
- Superseded by 7/1995 WET policy and 7/1990 rule requiring toxicity tests in POTW applications.
https://www.epa.gov/system/files/documents/2026-04/1985-guidance-wet-potws.pdf
National Combined Sewer Overflow Control Strategy National Combined Sewer Overflow Control Strategy (pdf) (713.85 KB) Strategy for control of discharges from combined sewer overflows.
- Updated by 4/19/1994 CSO Policy.
https://www.epa.gov/system/files/documents/2026-04/1989-cso-strategy.pdf
Guidance for Determination of Appropriate Methods for Detection of Section 313 Water Priority Chemicals Guidance for Determination of Appropriate Methods for Detection of Section 313 Water Priority Chemicals (pdf) (2.1 MB) Guidance to facilities discharging storm water and subject to EPCRA section 313 reporting requirements on what pollutants to sample for and what methods to use when sampling.https://www.epa.gov/system/files/documents/2026-04/1989-permit-strategy-ocpsf.pdf
New Regulations Governing the Discharge of Toxic and Hazardous Pollutants to Publicly Owned Treatment Works New Regulations Governing the Discharge of Toxic and Hazardous Pollutants to Publicly Owned Treatment Works (pdf) (556.69 KB) Memorandum describing applicability of 7/25/1990 regulations for control of toxic and hazardous pollutants on pretreatment and NPDES permitting programs.https://www.epa.gov/system/files/documents/2026-04/1990-pretreatment-regs-hazardous-waste.pdf
The Watershed Protection Approach - Framework Document
- With 10/28/1991 cover memo
The Watershed Protection Approach - Framework Document - With 10/28/1991 cover memo (pdf) (1.67 MB) Memorandum explaining the Office of Water approach for implementing a watershed approach.https://www.epa.gov/system/files/documents/2026-04/1991-watershed-framework.pdf
Reducing the NPDES Permit Backlog Reducing the NPDES Permit Backlog (pdf) (161.9 KB) Memorandum from J. Charles Fox to Regional Administrators about reducing the backlog of NPDES permits.https://www.epa.gov/system/files/documents/2026-04/1999-reducing-npdes-backlog.pdf
Agency Interpretation of Applicability of Section 402 of the CWA to Water Transfers Agency Interpretation of Applicability of Section 402 of the CWA to Water Transfers (pdf) (1.4 MB) Memorandum from Ann Klee and Ben Grumbles addresses whether NPDES program applies to water control facilities that merely connect or convey navigable waters.https://www.epa.gov/system/files/documents/2026-04/2005-agency-interpretation-water-transfers.pdf
Technical Guidance Manual - Regulations Promulgated Pursuant to Section 301(g) of the CWA of 1977 and 40 CFR Part 125 (Subpart F) Technical Guidance Manual - Regulations Promulgated Pursuant to Section 301(g) of the CWA of 1977 and 40 CFR Part 125 (Subpart F) (pdf) (9.61 MB) Guidance to EPA Regions and States on how to conduct technical analysis required in support of Section 301(g) variances to effluent guidelines.https://www.epa.gov/system/files/documents/2026-04/301g-variance-guidance.pdf
Questions and Answers on Implementation of Section 304(l) of the Clean Water Act Questions and Answers on Implementation of Section 304(l) of the Clean Water Act (pdf) (760.46 KB) Memorandum providing answers to miscellaneous questions about implementing section 304(l) of the CWA.https://www.epa.gov/system/files/documents/2026-04/304l-implementation-qsas.pdf
Interim Guidance on Implementation of Section 402(o) Antibacksliding Rules for Water Quality-Based Permits Interim Guidance on Implementation of Section 402(o) Antibacksliding Rules for Water Quality-Based Permits (pdf) (1.18 MB) Interprets CWA section 402(o) for water quality-based effluent limits and clarifies that the 1/4/1989 regulation interprets the Act for technology-based effluent limits.https://www.epa.gov/system/files/documents/2026-04/402o-wqbels.pdf
Concentrated Animal Feeding Operations - Final Rulemaking - Q & A Concentrated Animal Feeding Operations - Final Rulemaking - Q & A (pdf) (182.04 KB) Fact sheet provides questions and answers relating to the 2008 Final CAFO Rule.https://www.epa.gov/system/files/documents/2026-04/cafo-final-rule2008-qa.pdf
Clarification of "Instantaneous Maximum" as Applied to Steam Electric Facilities Effluent Limitations Clarification of "Instantaneous Maximum" as Applied to Steam Electric Facilities Effluent Limitations (pdf) (90.87 KB) Memorandum clarifying that steam electric effluent guideline for chlorine is intended to be an instantaneous maximum limit and not a daily maximum limit.https://www.epa.gov/system/files/documents/2026-04/clarification-tbel-steam-electric.pdf
Clarifications Regarding Certain Aspects of EPA's Surface Water Toxics Control Regulations Clarifications Regarding Certain Aspects of EPA's Surface Water Toxics Control Regulations (pdf) (397.86 KB) Clarifications of EPA's regulatory interpretations of the definition of whole effluent toxicity, the enforceability of limits based on a single toxicity test result, requirements for limits on pollutants and the use of indicator pollutants, use of state narrative water quality criteria, and standards for listing waters under CWA section 304(l).https://www.epa.gov/system/files/documents/2026-04/clarifications-304l-and-wqbel-regs.pdf
Eligibility for Variances Under Section 301(i)(l) of the CWA Eligibility for Variances Under Section 301(i)(l) of the CWA (pdf) (659.56 KB) Legal answers to several questions about eligibility for section 301(i) variances.https://www.epa.gov/system/files/documents/2026-04/clarify-potw-eligability-301h-variances.pdf
Storm Water Phase II - Compliance Assistance Guide Storm Water Phase II - Compliance Assistance Guide (pdf) (1.24 MB) Explains applicability of 12/9/1999 storm water regulations.https://www.epa.gov/system/files/documents/2026-04/comguide.pdf
Transmittal of Final 304(l) Implementation Guidance
- Cover memorandum only; guidance on separate row
Transmittal of Final 304(l) Implementation Guidance - Cover memorandum only; guidance on separate row (pdf) (100.05 KB) Cover memorandum for guidance to Regions and States on how to identify waters subject to listing under CWA section 304(l) and development of Individual Control Strategies for point sources discharging into these waters.https://www.epa.gov/system/files/documents/2026-04/cover-memo-304l-impl.pdf
Judicial Officer's Decision on Part 124 Proceedings Judicial Officer's Decision on Part 124 Proceedings (pdf) (593.35 KB) Guidance that when both legal and factual issues arise in an evidentiary hearing, and the EPA region grants the hearing on the factual issues, that the legal issues must also be heard by the administrative law judge.https://www.epa.gov/system/files/documents/2026-04/decision-part-124.pdf
Interim Strategy for the Regulation of Pulp and Paper Mill Discharges to the Waters of the U.S. Interim Strategy for the Regulation of Pulp and Paper Mill Discharges to the Waters of the U.S. (pdf) (476.3 KB) Strategy for writing permit limits to control dioxins and furans discharged from pulp and paper mills.
- Revised and finalized 5/21/1990.
https://www.epa.gov/system/files/documents/2026-04/dioxin-strategy-pulp-and-paper.pdf
Effluent Guidelines For the OCPSF Industrial Category Effluent Guidelines For the OCPSF Industrial Category (pdf) (590.89 KB) Interim guidance to permit authorities on application of new effluent guidelines for organic chemical facilities to NPDES permits.https://www.epa.gov/system/files/documents/2026-04/elg-ocpsf.pdf
Enforcement Efforts Addressing Sanitary Sewer Overflows Enforcement Efforts Addressing Sanitary Sewer Overflows (pdf) (116.82 KB) Memorandum discussing upcoming efforts to better understand SSO problems and possibility of drafting national guidance.https://www.epa.gov/system/files/documents/2026-04/enforcement-sso.pdf
Memorandum: Questions and Answers Regarding the OCPSF Effluent Limitations Guidelines Memorandum: Questions and Answers Regarding the OCPSF Effluent Limitations Guidelines (pdf) (854.94 KB) Memorandum and attachment providing frequently asked questions and answers related to the new effluent guideline for organic chemical plants.https://www.epa.gov/system/files/documents/2026-04/faq-ocpsf-elg.pdf
Fundamentally Different Factors Variances for Iron and Steel Facilities Fundamentally Different Factors Variances for Iron and Steel Facilities (pdf) (127.1 KB) Memorandum requesting answer on whether to consider "wholly disproportionate costs" on a facility or subcategory basis when processing an FDF variance, and expressing preference that a subcategory basis be used.https://www.epa.gov/system/files/documents/2026-04/fdf-variances-ironsteel.pdf
National Pollutant Discharge Elimination System (NPDES) Permitting for Environmental Results Strategy National Pollutant Discharge Elimination System (NPDES) Permitting for Environmental Results Strategy (pdf) (2.3 MB) Presents a coordinated and integrated management system that when fully implemented will produce an NPDES program that is more efficient and focuses on environmental results. This Strategy is an important element in an overall plan to meet the watershed restoration goals established in EPA's Strategic Plan.https://www.epa.gov/system/files/documents/2026-04/final-per-strategy.pdf
Fact sheet on Storm Water Program Phase II Extension Under the Water Resources Development Act Fact sheet on Storm Water Program Phase II Extension Under the Water Resources Development Act (pdf) (63.84 KB) Memorandum explaining that CWA was amended to extend storm water moratorium date from 10/1/1992 to 10/1/1994.https://www.epa.gov/system/files/documents/2026-04/fs-sw-phase-ii-extension.pdf
EPA's Authority to Issue NPDES General Permits in Approved NPDES States EPA's Authority to Issue NPDES General Permits in Approved NPDES States (pdf) (76.16 KB) Memorandum explaining that EPA has no authority to issue general permits in authorized States, where the State has yet to receive authority to issue general permits.https://www.epa.gov/system/files/documents/2026-04/gp-epa-authority.pdf
General Permit Program Guidance (cover memorandum)
- 3/1/1988 cover memorandum only; guidance is separate file
General Permit Program Guidance (cover memorandum) - 3/1/1988 cover memorandum only; guidance is separate file (pdf) (128.83 KB) Cover memorandum to guidance on issuance of general permits and authorization of state general permit programs.  Guidance also identifies which general permits EPA Headquarters will review (a provision rescinded in 6/29/1995 regulation).https://www.epa.gov/system/files/documents/2026-04/gp-program-cover-memo.pdf
The NPDES Permitting Process for Oil and Gas Activities on the Outer Continental Shelf
- With 7/3/1985 cover memo: "Transmittal of General Permitting Strategy for OCS Oil & Gas Activities Under EPA/MMS MOU"
The NPDES Permitting Process for Oil and Gas Activities on the Outer Continental Shelf - With 7/3/1985 cover memorandum: "Transmittal of General Permitting Strategy for OCS Oil & Gas Activities Under EPA/MMS MOU" (pdf) (1.17 MB) Guidance on developing NPDES permits for offshore oil and gas activities.https://www.epa.gov/system/files/documents/2026-04/guidance-npdes-ocs-oilgas.pdf
Clarification of Sampling Procedures for the VOA Fraction Clarification of Sampling Procedures for the VOA Fraction (pdf) (81.29 KB) Guidance on collecting and compositing samples containing volatile organics.https://www.epa.gov/system/files/documents/2026-04/guidance-sampling-voa.pdf
Final Guidance - Implementation of Requirements under Section 304(l) of the Clean Water Act As Amended
- Cover page and TOC only. Cover memorandum is separate document
Final Guidance - Implementation of Requirements under Section 304(l) of the Clean Water Act As Amended - Cover page and TOC only. Cover memorandum is separate document (pdf) (69.48 KB) Cover page and TOC for guidance to EPA Regions and States on how to identify waters subject to listing under CWA section 304(l) and development of Individual Control Strategies for point sources discharging into these waters.https://www.epa.gov/system/files/documents/2026-04/implementation-304l.pdf
Interim Petroleum Refinery Dioxin Discharges Activities and Guidance Update Interim Petroleum Refinery Dioxin Discharges Activities and Guidance Update (pdf) (495.01 KB) Memorandum providing an interim report on the available information regarding the potential presence of dioxins and furans in wastewater discharged from petroleum refineries and to provide the Regions with recommendations concerning notification of petroleum refineries about the detection of dioxins and furans in certain refinery wastestreams.https://www.epa.gov/system/files/documents/2026-04/int-report-dioxin-petrol-refinery.pdf
Clarification of CWA 316(b) Requirements for Liquified Natural Gas (LNG) Import Terminals Clarification of CWA 316(b) Requirements for Liquified Natural Gas (LNG) Import Terminals (pdf) (297.06 KB) Memorandum identifies requirements that apply or could potentially apply to cooling water intake structures at Liquified Natural Gas (LNG) import terminals under CWA Section 316(b).https://www.epa.gov/system/files/documents/2026-04/lng-clarification-memo.pdf
Delegation of Updates to Major/Minor Lists Delegation of Updates to Major/Minor Lists (pdf) (90.81 KB) Memorandum establishes delegation to Regions of determinations of major/minor status for municipal and non-municipal NPDES dischargers.https://www.epa.gov/system/files/documents/2026-04/majorminorlist.pdf
Coal Mining Under the Surface Mining Control and Reclamation Act of 1977 and Its Relationship to EPA's Current Responsibilities for Coal Mining Operations Coal Mining Under the Surface Mining Control and Reclamation Act of 1977 and Its Relationship to EPA's Current Responsibilities for Coal Mining Operations (pdf) (278.73 KB) Memorandum summarizing requirements of SMCRA and effect on NPDES permits.https://www.epa.gov/system/files/documents/2026-04/memo-1978-smcra.pdf
Clarifications on the Flexibility in 40 CFR Part 136 Whole Effluent Toxicity Test Methods Clarifications on the Flexibility in 40 CFR Part 136 Whole Effluent Toxicity Test Methods (pdf) (27.28 KB) Memorandum clarifying flexibility in regulations establishing analytical test methods for determining whole effluent toxicity.  Information to conduct WET test methods, for authorized States.https://www.epa.gov/system/files/documents/2026-04/memo-1996-clarifications-wet-methods.pdf
Applicability of Section 301(h) & (i) Modifications to Federal Facilities Applicability of Section 301(h) & (i) Modifications to Federal Facilities (pdf) (220.95 KB) Memorandum clarifying that because federal facilities are not POTWs, they are not authorized to receive 301(h) or 301(i) waivers.https://www.epa.gov/system/files/documents/2026-04/memo-applicability-301h-301i-ff.pdf
Authorization of Partial State Sewage Sludge Programs Authorization of Partial State Sewage Sludge Programs (pdf) (300.03 KB) Memorandum stating that states can request authorization for parts of the sludge permit program.    https://www.epa.gov/system/files/documents/2026-04/memo-biosolids-partial-auth.pdf
Annual Permit Limits for Nitrogen & Phosphorus for Permits Designed to Protect Chesapeake Bay & Its Tidal Tributaries from Excess Nutrient Loading Under NPDES Annual Permit Limits for Nitrogen & Phosphorus for Permits Designed to Protect Chesapeake Bay & Its Tidal Tributaries from Excess Nutrient Loading Under NPDES (pdf) (23.04 KB) Memorandum from Jim Hanlon to Region 3 and Chesapeake Bay Program Office concurring on use of annual permit limits for nitrogen and phosphorus.https://www.epa.gov/system/files/documents/2026-04/memo-chesapeakebay.pdf
Approach Taken By Michigan to Regulate Storm Water Discharges from Construction Activities Approach Taken By Michigan to Regulate Storm Water Discharges from Construction Activities (pdf) (1.4 MB) Memorandum providing guidance to the regions on an approach, used by the state of Michigan, which could be used to regulate storm water discharges from construction activities.https://www.epa.gov/system/files/documents/2026-04/memo-construction-sw-mi.pdf
Enforcement Policy and the Use of Enforcement Compliance Schedule Letters (ECSLs) for Publicly Owned Treatment Works (POTWs) Enforcement Policy and the Use of Enforcement Compliance Schedule Letters (ECSLs) for Publicly Owned Treatment Works (POTWs) (pdf) (167.6 KB) Memorandum clarifying that enforcement compliance schedule letters are only applicable to certain POTWs.

https://www.epa.gov/system/files/documents/2026-04/memo-ecls-potws1.pdf

Procedures for Processing Fundamentally Different Factors Variances Procedures for Processing Fundamentally Different Factors Variances (pdf) (205.65 KB) Memorandum identifying regulatory requirements for processing FDF variances.https://www.epa.gov/system/files/documents/2026-04/memo-fdf-variances.pdf
NPDES Permits and Requirements of State Law NPDES Permits and Requirements of State Law (pdf) (169.44 KB) Memorandum expressing that NPDES permits to federal facilities must conform with state water quality management plans, but need not be immediately modified to include recent revisions to such plans.https://www.epa.gov/system/files/documents/2026-04/memo-ff-state-law-requirements.pdf
Applicability of General Permits to New Sources Applicability of General Permits to New Sources (pdf) (85.41 KB) Memorandum explains that general permits can include new sources, but only after NEPA requirements are fulfilled.https://www.epa.gov/system/files/documents/2026-04/memo-gp-newsource.pdf
Use of In-Stream Mechanical Aerators to Meet Water Quality Standards Use of In-Stream Mechanical Aerators to Meet Water Quality Standards (pdf) (159.46 KB) Memorandum recommending that use of instream aerators not be considered analogous to low flow augmentation.https://www.epa.gov/system/files/documents/2026-04/memo-instream-aerators.pdf
Use of Low Flow Augmentation by Point Sources to Meet Water Quality Standards Use of Low Flow Augmentation by Point Sources to Meet Water Quality Standards (pdf) (485.01 KB) Memorandum explaining EPA's policy discouraging use of flow augmentation as an alternative to treatment for meeting water quality standards.https://www.epa.gov/system/files/documents/2026-04/memo-lowflow-augmentation.pdf
Municipal Wastewater Treatment Ponds Municipal Wastewater Treatment Ponds (pdf) (237.26 KB) Guidance on permitting and enforcement activities under new regulation allowing municipal wastewater treatment ponds to satisfy secondary treatment requirements.https://www.epa.gov/system/files/documents/2026-04/memo-muni-ww-treatment-ponds.pdf
Determining Whether Revisions to State NPDES Programs Made to Authorize the Issuance of General Permits are Substantial Determining Whether Revisions to State NPDES Programs Made to Authorize the Issuance of General Permits are Substantial (pdf) (119.2 KB) In response to Regional and State comments, re-interprets which state program revisions are "substantial."https://www.epa.gov/system/files/documents/2026-04/memo-npdes-prog-rev-substantial.pdf
NPDES Permits in Wetlands Areas NPDES Permits in Wetlands Areas (pdf) (104.9 KB) Memorandum explaining that, in most cases, an NPDES permit resulting from the creation of a landfill in a wetlands would be denied.https://www.epa.gov/system/files/documents/2026-04/memo-npdes-wetland.pdf
Additional Guidance for Petroleum Marketing Terminals & Oil Production Facilities Additional Guidance for Petroleum Marketing Terminals & Oil Production Facilities (pdf) (274.32 KB) Memorandum explains that oil and grease monitoring for petroleum marketing terminals and oil production facilities must use daily maximum limits, not instantaneous maximum limits.
-Supersedes 3/18/1974 memorandum.
https://www.epa.gov/system/files/documents/2026-04/memo-oilgrease-monitoring.pdf
Expediting Achievement of Water Quality Improvements by 301(h) Applicants Expediting Achievement of Water Quality Improvements by 301(h) Applicants (pdf) (341.61 KB) Memorandum establishing required actions to expedite compliance with the CWA for POTWs discharging offshore that request a variance from secondary treatment.https://www.epa.gov/system/files/documents/2026-04/memo-potw-compliance-301h.pdf
Statutory Deadlines for Compliance by Publicly Owned Treatment Works Under the Clean Water Act Statutory Deadlines for Compliance by Publicly Owned Treatment Works Under the Clean Water Act (pdf) (324.13 KB) Legal memorandum explaining that although the 1981 CWA amendments extended the opportunity for 301(i) variances to 7/1/1988, this does not authorize granting compliance schedules for POTWs that have not received this variance.https://www.epa.gov/system/files/documents/2026-04/memo-potw-compliance-deadline.pdf
Suspended Solids Effluent Limitations for Publicly Owned Wastewater Treatment Ponds Followed by Other Treatment Elements Suspended Solids Effluent Limitations for Publicly Owned Wastewater Treatment Ponds Followed by Other Treatment Elements (pdf) (401.72 KB) Policy stating when the secondary treatment requirement for total suspended solids can be adjusted.https://www.epa.gov/system/files/documents/2026-04/memo-potw-tss.pdf
Calculation of Production-Based Effluent Limits Calculation of Production-Based Effluent Limits (pdf) (302.92 KB) Memorandum clarifying procedure for calculating production based effluent limitations and on the use of alternate limitations.https://www.epa.gov/system/files/documents/2026-04/memo-production-based-tbels.pdf
Interpretive Policy Memorandum on Reapplication Requirements for Municipal Separate Storm Sewer Systems Interpretive Policy Memorandum on Reapplication Requirements for Municipal Separate Storm Sewer Systems (pdf) (108.5 KB) Interpretive policy memorandum clarifies regulations addressing reapplication requirements.  Explains that MS4 permit applicants and NPDES permit writers have considerable discretion to customize appropriate and streamlined reapplication requirements on a case-by-case basis.https://www.epa.gov/system/files/documents/2026-04/memo-reapplication-req-ms4.pdf
Regional Review of State-Issued NPDES Permits Regional Review of State-Issued NPDES Permits (pdf) (123.3 KB) Memorandum clarifying that EPA's review of State issued permits is not an approval because the CWA only allows EPA to veto State-issued permits.https://www.epa.gov/system/files/documents/2026-04/memo-reg-rev-st-issued-permits.pdf
Remand of Restoration Provisions in Rule Governing Cooling Water Intakes at New Facilities under Section 316(b) of the CWA Remand of Restoration Provisions in Rule Governing Cooling Water Intakes at New Facilities under Section 316(b) of the CWA (pdf) (94 KB) Memorandum discusses the remand of restoration measures for 316(b) Phase I New facilities.https://www.epa.gov/system/files/documents/2026-04/memo-remand.pdf
Sewage Disposal from Trains Sewage Disposal from Trains (pdf) (118.73 KB) Memorandum clarifying that sewage disposal from trains is best addressed by the Rail Passenger Service Act, and not the CWA.https://www.epa.gov/system/files/documents/2026-04/memo-sewage-trains.pdf
State Pretreatment Programs State Pretreatment Programs (pdf) (390.73 KB) Memorandum expressing allowable flexibility in developing and implementing State pretreatment programs.https://www.epa.gov/system/files/documents/2026-04/memo-st-pretreatment.pdf
Clarification of OGC Opinion No. 40 (State Review Authority) Clarification of OGC Opinion No. 40 (State Review Authority) (pdf) (110.53 KB) Legal memorandum clarifying that states have same authority as EPA Regions in considering economic impact of technology based effluent limits, when establishing these limits using best professional judgment.https://www.epa.gov/system/files/documents/2026-04/memo-state-authority-tbel-bpj1.pdf
State General Permit Program Development State General Permit Program Development (pdf) (6.42 MB) Under the cover titled "General Permit Program Guidance" are the following documents to help states gain authority for general permit issuance:
- 6/13/1989 memorandum "Development of State NPDES Permit Programs" (pp. 3-4 of PDF file)
- 6/13/1989 guidance "State General Permits Program Development" (pp. 5-30 of PDF file)
- 2/1988 guidance "General Permit Program Guidance" (pp. 31-133 of PDF file).
The 6/1989 documents supplement the 2/1988 guidance.
https://www.epa.gov/system/files/documents/2026-04/memo-state-gp-authority.pdf
State Regulation of Federal Facilities Under the Federal Water Pollution Control Act Amendments of 1977 (Clean Water Act) - Policy Guidance Memorandum State Regulation of Federal Facilities Under the Federal Water Pollution Control Act Amendments of 1977 (Clean Water Act) - Policy Guidance Memorandum (pdf) (410.43 KB) Memorandum clarifying that States can issue NPDES permits to federal facilities, but only after receiving authority to do so from EPA.https://www.epa.gov/system/files/documents/2026-04/memo-state-npdes-permits-ff.pdf
Policy for End of Moratorium for Stormwater Permitting - October 1, 1994 Policy for End of Moratorium for Stormwater Permitting - October 1, 1994 (pdf) (267.26 KB) Memorandum describing EPA's approach for dealing with phase II storm water sources after October 1, 1994.https://www.epa.gov/system/files/documents/2026-04/memo-sw-phase-ii-application-req.pdf
Policy Regarding the Inclusion in Permits of Effluent Parameters More Stringent Than or Additional to Those Based on Secondary Treatment or Effluent Guidelines Policy Regarding the Inclusion in Permits of Effluent Parameters More Stringent Than or Additional to Those Based on Secondary Treatment or Effluent Guidelines (pdf) (359.84 KB) Policy expressing when effluent limitations in addition to those required by effluent guidelines or secondary treatment can be included in permits.https://www.epa.gov/system/files/documents/2026-04/memo-tbel-more-stingent-elg.pdf
The Watershed Approach: Our Framework for Ecosystem Protection The Watershed Approach: Our Framework for Ecosystem Protection (pdf) (604.54 KB) Memorandum describing actions EPA will take to foster a watershed approach to protecting surface waters.https://www.epa.gov/system/files/documents/2026-04/memo-watershed-framework.pdf
Use of Biomonitoring in the NPDES Permits Program Use of Biomonitoring in the NPDES Permits Program (pdf) (797.63 KB) Legal memorandum explaining that EPA has authority to require biomonitoring and establish non-effluent guideline limitations for toxics in NPDES permits.https://www.epa.gov/system/files/documents/2026-04/memo-wet-biomonitoring.pdf
Disposal of Supply Water Treatment Sludges Disposal of Supply Water Treatment Sludges (pdf) (113.04 KB) Memorandum explaining EPA position that while discharge of wastewater treatment sludges is not allowed, discharge of water treatment sludges may be allowed, under NPDES regulations.https://www.epa.gov/system/files/documents/2026-04/memo-wwtp-sludge.pdf
Model NPDES Permit for Discharges from the Cleanup of Gasoline Released from Underground Storage Tanks Model NPDES Permit for Discharges from the Cleanup of Gasoline Released from Underground Storage Tanks (pdf) (3.92 MB) Model permit for technology-based controls on discharges from cleanup operations for gasoline leaks from underground storage tanks.https://www.epa.gov/system/files/documents/2026-04/model-permit-tbels-ust.pdf
Applicability of 2008 MSGP to Gravel Pits Associated with Road & Bridge Construction & Maintenance Applicability of 2008 MSGP to Gravel Pits Associated with Road & Bridge Construction & Maintenance (pdf) (1020.48 KB) Clarifies the applicability of the recently issued 2008 Multi-Sector General Permit for Stormwater Discharges Associated with Industrial Activity to gravel pits that supply material to road and bridge construction and maintenance projects.https://www.epa.gov/system/files/documents/2026-04/msgp2008-sand-and-gravel.pdf
NPDES Permit Writer's Guide on Data Quality Objectives NPDES Permit Writer's Guide on Data Quality Objectives (pdf) (3.5 MB) Guidance to help permit writers ensure that environmental data collected or required by NPDES permits will be adequate for decision-making.https://www.epa.gov/system/files/documents/2026-04/npdes-data-quality-objectives.pdf
NPDES Permit Issuance for Pulp and Paper Facilities and Issuance of Permits with BCT Limitations to Other Facilities NPDES Permit Issuance for Pulp and Paper Facilities and Issuance of Permits with BCT Limitations to Other Facilities (pdf) (175.87 KB) Memorandum discussing EPA's position on regulation of Pulp and Paper Industrial Point Source Category, examining methods for issuance of permits to facilities in that category and issuance of permits with BCT limits to secondary categories other than pulp and paper.https://www.epa.gov/system/files/documents/2026-04/npdes-tbels-pulp-and-paper.pdf
NPDES Permitting Strategy for OCPSF Industry Direct Dischargers NPDES Permitting Strategy for OCPSF Industry Direct Dischargers (pdf) (3.6 MB) National strategy calling for expeditious reissuance of NPDES permits for organic chemical facilities, in order that the new effluent guidelines can quickly become implemented.https://www.epa.gov/system/files/documents/2026-04/permit-strategy-ocpsf.pdf
Permitting for Environmental Results - Permit Issuance and Priority Permits Permitting for Environmental Results - Permit Issuance and Priority Permits (pdf) (56.58 KB) Procedures for identifying environmentally significant priority permits; and asks Regions and States to incorporate these procedures.https://www.epa.gov/system/files/documents/2026-04/prioritization-memo.pdf
Process for Obtaining Clean Water Act Section 401 Certification for EPA-Issued NPDES Permits Process for Obtaining Clean Water Act Section 401 Certification for EPA-Issued NPDES Permits (pdf) (451.7 KB) Memorandum clarifies procedures for obtaining 401 certifications.https://www.epa.gov/system/files/documents/2026-04/process-401-cert-epa-npdes-permits.pdf
Guidance on Pretreatment Program Modification Requirements of 40 CFR 403.18
- With cover memo: 40 CFR 403.18 Pretreatment Program Modifications
Guidance on Pretreatment Program Modification Requirements of 40 CFR 403.18 - With cover memo: 40 CFR 403.18 Pretreatment Program Modifications (pdf) (122.76 KB) Provides guidance on implementation of 403.18 procedures for approving changes to approved pretreatment programs. Suggests how states and EPA approval authorities might reduce effort to comply with 403.18, especially public notice requirements.https://www.epa.gov/system/files/documents/2026-04/promod.pdf
Revised Policy Statement on Scope of Discharge Authorization and Shield Associated with NPDES Permits Revised Policy Statement on Scope of Discharge Authorization and Shield Associated with NPDES Permits (pdf) (383.94 KB) Changes to 7/1/1994 policy outlining EPA's interpretation of CWA section 402(k), also known as "permit as a shield."https://www.epa.gov/system/files/documents/2026-04/revised-1994-memo-npdes-authorization-sheild.pdf
Whole Effluent Toxicity Sample Permitting & Enforcement Guidance
- Attaches 2/2/1989 memo "Whole Effluent Toxicity Basic Permitting Principles and Enforcement Strategy"
Whole Effluent Toxicity Sample Permitting & Enforcement Guidance - Attaches 2/2/1989 memo "Whole Effluent Toxicity Basic Permitting Principles and Enforcement Strategy" (pdf) (1.82 MB) Sample permit language to improve consistency in whole effluent toxicity limits in NPDES permits.https://www.epa.gov/system/files/documents/2026-04/sample-permit-wet.pdf
Representative Sampling in NPDES Permits Representative Sampling in NPDES Permits (pdf) (124.75 KB) Memorandum expressing importance of clear expressions of monitoring locations in NPDES permits, and recommending appropriate permit language.https://www.epa.gov/system/files/documents/2026-04/sampling-npdes.pdf
Strategy for the Regulation of Discharges of PHDDs and PHDFs from Pulp and Paper Mills to Waters of the U.S. Strategy for the Regulation of Discharges of PHDDs and PHDFs from Pulp and Paper Mills to Waters of the U.S. (pdf) (2.81 MB) Strategy for writing permit limits to control dioxins and furans discharged from pulp and paper mills.  
- Replaces 8/9/1988 interim strategy.
https://www.epa.gov/system/files/documents/2026-04/strategy-dioxins-pulp-and-paper.pdf
Revisions to Stormwater Regulations to Clarify that an NPDES Permit is not Required for Stormwater Discharges from Logging Roads (EPA-HQ-OW-2012-0195) Revisions to Stormwater Regulations to Clarify that an NPDES Permit is not Required for Stormwater Discharges from Logging Roads (EPA-HQ-OW-2012-0195) (pdf) (140.69 KB) Fact sheet describes "revised Phase I stormwater regulations to clarify that stormwater discharges from logging roads do not constitute stormwater discharges associated with industrial activity and that an NPDES permit is not required for these stormwater discharges."https://www.epa.gov/system/files/documents/2026-04/sw-forestroad-factsheet1.pdf
Anticipated Questions on Revisions to Stormwater Regulations to Clarify that an NPDES Permit is not Required for Stormwater Discharges from Logging Roads Anticipated Questions on Revisions to Stormwater Regulations to Clarify that an NPDES Permit is not Required for Stormwater Discharges from Logging Roads (pdf) (108.99 KB) Qs and As addressing revisions to stormwater regulationshttps://www.epa.gov/system/files/documents/2026-04/sw-forestroad-faq.pdf
Interpretive Statement & Regional Guidance - CWA's Exemption for Return Flows from Irrigated Agriculture Interpretive Statement & Regional Guidance - CWA's Exemption for Return Flows from Irrigated Agriculture (pdf) (37.95 KB) In Headwaters, Inc. vs. Talent Irrigation District, the U.S. Court of Appeals for the Ninth Circuit held that an applicator of aquatic herbicides was required to obtain a NPDES permit under the CWA.https://www.epa.gov/system/files/documents/2026-04/talentfinal.pdf
NPDES Permit Issuance Flexibility Policy in Watershed Permitting NPDES Permit Issuance Flexibility Policy in Watershed Permitting (pdf) (214.23 KB) Memorandum to Regions recognizing challenges of meeting permit issuance requirements during the transition to the watershed approach.  Outlines measures to facilitate transition.https://www.epa.gov/system/files/documents/2026-04/wbp-flexability-policy.pdf
Contact Us About NPDES to ask a question, provide feedback, or report a problem.
Last updated on April 16, 2026
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