40 CFR § 438.12 - Effluent limitations attainable by the application of the best practicable control technology currently available (BPT).

---
identifier: "/us/cfr/t40/s438.12"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 438.12 - Effluent limitations attainable by the application of the best practicable control technology currently available (BPT)."
title_number: 40
title_name: "Protection of Environment"
section_number: "438.12"
section_name: "Effluent limitations attainable by the application of the best practicable control technology currently available (BPT)."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "N"
subchapter_name: "EFFLUENT GUIDELINES AND STANDARDS"
part_number: "438"
part_name: "METAL PRODUCTS AND MACHINERY POINT SOURCE CATEGORY"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "33 U.S.C. 1311, 1314, 1316, 1317, 1318, 1342 and 1361."
regulatory_source: "68 FR 25735, May 13, 2003, unless otherwise noted."
cfr_part: "438"
---


# 438.12 Effluent limitations attainable by the application of the best practicable control technology currently available (BPT).

Except as provided at 40 CFR 125.30 through 125.32, any existing point source subject to this subpart must achieve the following effluent limitations representing the application of BPT. Discharges must remain within the pH range 6 to 9 and must not exceed the following:

Effluent Limitations

[BPT]

| Regulated parameter | Maximum daily |
| --- | --- |
| 1. TSS | 62 |
| 2. O&G (as HEM) | 46 |
| mg/L (ppm). |  |