Final rule · 2025-18816

Water Quality Standards To Protect Aquatic Life in the Delaware River

The U.S. Environmental Protection Agency (EPA) is finalizing revised water quality standards (WQS) largely as proposed for certain water quality management zones of the mainstem Delaware River under the Clean Water Act (CWA). Specifically, the EPA is promulgating a designated use of protection and propagation of resident and migratory aquatic life and corresponding dissolved oxygen water quality criteria for the mainstem Delaware River in Zone 3, Zone 4, and the upper portion of Zone 5 (in total, river miles 108.4 to 70.0).