Regulations last checked for updates: Feb 07, 2026

Title 40 - Protection of Environment last revised: Dec 22, 2026
§ 429.95 - Pretreatment standards for existing sources (PSES).

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 meet the following pretreatment standards for existing sources (PSES):

Subpart H

[PSES Effluent Limitations]

Pollutant or pollutant property Maximum for any 1 day (mg/l)
Oil and grease100
Copper5
Chromium4
Arsenic4
In cases where POTWs find it necessary to impose mass limitations, the following equivalent mass limitations are provided as guidance.

Subpart H

[PSES Effluent Limitations; grams per cu m of production]

Pollutant or pollutant property Maximum for any 1 day
Oil and grease20.5
Copper.62
Chromium.41
Arsenic.41
source: 46 FR 8285, Jan. 26, 1981, unless otherwise noted.
cite as: 40 CFR 429.95