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Title 40

Displaying title 40, up to date as of 8/10/2026. Title 40 was last amended 8/07/2026.
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Title 40Protection of EnvironmentPart / Section
Chapter IEnvironmental Protection Agency1 – 1099
Subchapter DWater Programs100 – 149
Part 122EPA Administered Permit Programs: the National Pollutant Discharge Elimination System122.1 – 122.64
Subpart ADefinitions and General Program Requirements122.1 – 122.7
§ 122.1Purpose and scope.
§ 122.2Definitions.
§ 122.3Exclusions.
§ 122.4Prohibitions (applicable to State NPDES programs, see § 123.25).
§ 122.5Effect of a permit.
§ 122.6Continuation of expiring permits.
§ 122.7Confidentiality of information.
Subpart BPermit Application and Special NPDES Program Requirements122.21 – 122.38
Subpart CPermit Conditions122.41 – 122.50
Subpart DTransfer, Modification, Revocation and Reissuance, and Termination of Permits122.61 – 122.64
§ 122.61Transfer of permits (applicable to State programs, see § 123.25).
§ 122.62Modification or revocation and reissuance of permits (applicable to State programs, see § 123.25).
§ 122.63Minor modifications of permits.
§ 122.64Termination of permits (applicable to State programs, see § 123.25).
Appendix A to Part 122
NPDES Primary Industry Categories
Appendix B to Part 122 [Reserved]
Appendix C to Part 122
Criteria for Determining a Concentrated Aquatic Animal Production Facility (§ 122.24)
Appendix D to Part 122
NPDES Permit Application Testing Requirements (§ 122.21)
Appendix E to Part 122
Rainfall Zones of the United States
Appendix F to Part 122
Incorporated Places With Populations Greater Than 250,000 According to the 1990 Decennial Census by the Bureau of the Census
Appendix G to Part 122
Incorporated Places With Populations Greater Than 100,000 But Less Than 250,000 According to the 1990 Decennial Census by the Bureau of the Census
Appendix H to Part 122
Counties With Unincorporated Urbanized Areas With a Population of 250,000 or More According to the 1990 Decennial Census by the Bureau of the Census
Appendix I to Part 122
Counties With Unincorporated Urbanized Areas Greater Than 100,000, But Less Than 250,000 According to the 1990 Decennial Census by the Bureau of the Census
Appendix J to Part 122
NPDES Permit Testing Requirements for Publicly Owned Treatment Works (§ 122.21(j))