An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Section 404 of the Clean Water Act

2019 Redwood City Salt Plant Jurisdictional Determination under CWA Section 404

In March 2015, EPA announced that it was exercising its “special case” authority under the 1989 Memorandum of Agreement between EPA and the Department of the Army: Determination of Geographic Jurisdiction of the Clean Water Act Section 404 Program to make the CWA jurisdictional determination for the Redwood City Salt Plant site in California.

In March 2019, EPA finalized its jurisdictional determination for this site. In making its determination, EPA relied on the agency's and the Corps’ long-recognized legal interpretation that CWA jurisdiction does not apply to waters that were legally converted to dry land (i.e., “fast land”) by permit, or prior to the passage of the CWA. After careful legal consideration and review, EPA has found that the Redwood City Salt Plant site does not include “waters of the United States” because the site was converted to fast land long before the CWA was enacted.

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.