Regulations last checked for updates: Dec 17, 2025

Title 40 - Protection of Environment last revised: Nov 17, 2028
§ 439.4 - General limitation or standard for pH.

The pH must remain within the range 6.0 to 9.0 in any discharge subject to BPT, BCT or NSPS limitations or standards in this part.

[68 FR 12271, Mar. 13, 2003]
source: 48 FR 49821, Oct. 27, 1983, unless otherwise noted.
cite as: 40 CFR 439.4