The Phase II stormwater regulations are a set of regulations that were published in December 1999, becoming effective March 2003, that are intended to guide local communities in the development of strategies to educate the public, to prepare local legislation, and to inspect stormwater collection and conveyance systems to promote the protection and preservation of water quality through stormwater management.

The Phase II stormwater regulations were an extension of the Phase I stormwater program that was initiated by Congress in 1992. The Phase I regulations required large communities with populations greater than 100,000 to apply for individual stormwater permits.