StacksVerified U.S. regulatory reference

40 CFR §141.501

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
You are subject to these requirements if your system:
  1. (a)Is a public water system;
  2. (b)Uses surface water or GWUDI as a source; and
  3. (c)Serves fewer than 10,000 persons.