40 CFR § 141.520 - Is my system subject to the updated watershed control requirements?

---
identifier: "/us/cfr/t40/s141.520"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 141.520 - Is my system subject to the updated watershed control requirements?"
title_number: 40
title_name: "Protection of Environment"
section_number: "141.520"
section_name: "Is my system subject to the updated watershed control requirements?"
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "D"
subchapter_name: "WATER PROGRAMS"
part_number: "141"
part_name: "NATIONAL PRIMARY DRINKING WATER REGULATIONS"
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: "40 FR 59570, Dec. 24, 1975, unless otherwise noted."
cfr_part: "141"
---


# 141.520 Is my system subject to the updated watershed control requirements?

If you are a subpart H system serving fewer than 10,000 persons which does not provide filtration, you must continue to comply with all of the filtration avoidance criteria in § 141.71, as well as the additional watershed control requirements in § 141.521.