An official website of the United States government.

We've made some changes to EPA.gov. If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Impaired Waters and TMDLs

Overview of the Impaired Waters and TMDLs Program under CWA Section 303(d)

Learn about identifying and restoring impaired waters under Section 303(d) of the Clean Water Act (CWA).  Below is information about what Section 303(d) authorizes, how the listing and restoration processes works, and  what TMDLs are.