StacksVerified U.S. regulatory reference

40 CFR §141.520

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
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.