StacksVerified U.S. regulatory reference

40 CFR §437.21

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Except as provided in 40 CFR 125.30 through 125.32 or § 437.20(b), any existing point source subject to this subpart must achieve the following effluent limitations representing the application of BPT: