40 CFR § 429.75
Pretreatment standards for existing sources (PSES)
June 9, 2020
Except as provided in 40 CFR 403.7 and 403.13, any existing source subject to this subpart which introduces process wastewater pollutants into a publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for existing sources (PSES): There shall be no introduction of process wastewater pollutants into publicly owned treatment works.