40 CFR § 437.25 - Pretreatment standards for existing sources (PSES).

---
identifier: "/us/cfr/t40/s437.25"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 437.25 - Pretreatment standards for existing sources (PSES)."
title_number: 40
title_name: "Protection of Environment"
section_number: "437.25"
section_name: "Pretreatment standards for existing sources (PSES)."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "N"
subchapter_name: "EFFLUENT GUIDELINES AND STANDARDS"
part_number: "437"
part_name: "THE CENTRALIZED WASTE TREATMENT POINT SOURCE CATEGORY"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "33 U.S.C. 1311, 1314, 1316, 1317, 1318, 1342, and 1361."
regulatory_source: "65 FR 81300, Dec. 22, 2000, unless otherwise noted."
cfr_part: "437"
---


# 437.25 Pretreatment standards for existing sources (PSES).

Except as provided in 40 CFR 403.7, 403.13 or § 437.20(b), and no later than December 22, 2003, any existing source subject to this subpart must achieve the following pretreatment standards:

Pretreatment Standards (PSES)

| Regulatedparameter | Maximum daily | Maximum monthly avg. |
| --- | --- | --- |
|  |  |  |
| Chromium | 0.947 | 0.487 |
| Cobalt | 56.4 | 18.8 |
| Copper | 0.405 | 0.301 |
| Lead | 0.222 | 0.172 |
| Tin | 0.249 | 0.146 |
| Zinc | 6.95 | 4.46 |
|  |  |  |
| Bis(2-ethylhexyl) phthalate | 0.267 | 0.158 |
| Carbazole | 0.392 | 0.233 |
| n-Decane | 5.79 | 3.31 |
| Fluoranthene | 0.787 | 0.393 |
| n-Octadecane | 1.22 | 0.925 |
| mg/L (ppm). |  |  |

[65 FR 81300, Dec. 22, 2000, as amended at 68 FR 71023, Dec. 22, 2003]