40 CFR § 142.4 - State and local authority.

---
identifier: "/us/cfr/t40/s142.4"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 142.4 - State and local authority."
title_number: 40
title_name: "Protection of Environment"
section_number: "142.4"
section_name: "State and local authority."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "D"
subchapter_name: "WATER PROGRAMS"
part_number: "142"
part_name: "NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-4, 300j-9, and 300j-11."
regulatory_source: "41 FR 2918, Jan. 20, 1976, unless otherwise noted."
cfr_part: "142"
---


# 142.4 State and local authority.

Nothing in this part shall diminish any authority of a State or political subdivision to adopt or enforce any law or regulation respecting drinking water regulations or public water systems, but no such law or regulation shall relieve any person of any requirements otherwise applicable under this part.