• Part 400 - PART 400 [RESERVED]

• Part 401 [§ 401.10 - § 401.17] - PART 401—GENERAL PROVISIONS

• Part 402 - PART 402 [RESERVED]

• Part 403 [§ 403.1 - § 403.20] - PART 403—GENERAL PRETREATMENT REGULATIONS FOR EXISTING AND NEW SOURCES OF POLLUTION

• Part 405 [§ 405.10 - § 405.127] - PART 405—DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY

• Part 406 [§ 406.10 - § 406.107] - PART 406—GRAIN MILLS POINT SOURCE CATEGORY

• Part 407 [§ 407.10 - § 407.87] - PART 407—CANNED AND PRESERVED FRUITS AND VEGETABLES PROCESSING POINT SOURCE CATEGORY

• Part 408 [§ 408.10 - § 408.337] - PART 408—CANNED AND PRESERVED SEAFOOD PROCESSING POINT SOURCE CATEGORY

• Part 409 [§ 409.10 - § 409.87] - PART 409—SUGAR PROCESSING POINT SOURCE CATEGORY

• Part 410 [§ 410.00 - § 410.97] - PART 410—TEXTILE MILLS POINT SOURCE CATEGORY

• Part 411 [§ 411.10 - § 411.37] - PART 411—CEMENT MANUFACTURING POINT SOURCE CATEGORY

• Part 412 [§ 412.1 - § 412.47] - PART 412—CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY

• Part 413 [§ 413.01 - § 413.84] - PART 413—ELECTROPLATING POINT SOURCE CATEGORY

• Part 414 [§ 414.10 - § 414.111] - PART 414—ORGANIC CHEMICALS, PLASTICS, AND SYNTHETIC FIBERS

• Part 415 [§ 415.01 - § 415.677] - PART 415—INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY

• Part 416 - PART 416 [RESERVED]

• Part 417 [§ 417.10 - § 417.196] - PART 417—SOAP AND DETERGENT MANUFACTURING POINT SOURCE CATEGORY

• Part 418 [§ 418.10 - § 418.77] - PART 418—FERTILIZER MANUFACTURING POINT SOURCE CATEGORY

• Part 419 [§ 419.10 - § 419.57] - PART 419—PETROLEUM REFINING POINT SOURCE CATEGORY

• Part 420 [§ 420.01 - § 420.137] - PART 420—IRON AND STEEL MANUFACTURING POINT SOURCE CATEGORY

• Part 421 [§ 421.1 - § 421.337] - PART 421—NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY

• Part 422 [§ 422.10 - § 422.67] - PART 422—PHOSPHATE MANUFACTURING POINT SOURCE CATEGORY

• Part 423 [§ 423.10 - § 423.19] - PART 423—STEAM ELECTRIC POWER GENERATING POINT SOURCE CATEGORY

• Part 424 [§ 424.10 - § 424.77] - PART 424—FERROALLOY MANUFACTURING POINT SOURCE CATEGORY