Protection of Environment. Part450:Construction and development point source category. Section450.21:Effluent limitations reflecting the best practicable technology currently available (BPT).
Except as provided in 40 CFR 125.30 through 125.32, any point source subject to this subpart must achieve, at a minimum, the following effluent limitations representing the degree of effluent reduction attainable by application of the best practicable control technology currently available (BPT).