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Regulations last checked for updates: May 17, 2025
Title 40 - Protection of Environment last revised: Nov 17, 2025
All Titles
Title 40
Chapter I
Part 131 - PART 131—WATER QUALITY STANDARDS
Subpart A [§ 131.1 - § 131.8] - Subpart A—General Provisions
Subpart B [§ 131.9 - § 131.15] - Subpart B—Establishment of Water Quality Standards
Subpart C [§ 131.20 - § 131.22] - Subpart C—Procedures for Review and Revision of Water Quality Standards
Subpart D [§ 131.31 - § 131.47] - Subpart D—Federally Promulgated Water Quality Standards
authority:
33 U.S.C. 1251
source:
48 FR 51405, Nov. 8, 1983, unless otherwise noted.
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