40 CFR § 125.1 - Purpose and scope.

---
identifier: "/us/cfr/t40/s125.1"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 125.1 - Purpose and scope."
title_number: 40
title_name: "Protection of Environment"
section_number: "125.1"
section_name: "Purpose and scope."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "D"
subchapter_name: "WATER PROGRAMS"
part_number: "125"
part_name: "CRITERIA AND STANDARDS FOR THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "The Clean Water Act, 33 U.S.C. 1251  unless otherwise noted."
regulatory_source: "44 FR 32948, June 7, 1979, unless otherwise noted."
cfr_part: "125"
---


# 125.1 Purpose and scope.

This subpart establishes criteria and standards for the imposition of technology-based treatment requirements in permits under section 301(b) of the Act, including the application of EPA promulgated effluent limitations and case-by-case determinations of effluent limitations under section 402(a)(1) of the Act.