The Storm Water Phase II Rule is the next step in United States Environmental Protection Agency's (U.S. EPA) effort to preserve, protect, and improve the nation's water resources from polluted storm water runoff. Phase II is intended to further reduce adverse water quality and aquatic habitat conditions by instituting the use of controls on the unregulated sources of storm water discharges that have the greatest likelihood of causing environmental degradation.

The Phase II rule automatically covers on a nationwide basis all small Municipal Separate Storm Sewer Systems (MS4s) located in "Urbanized Areas" as delineated by the Census Bureau, and those potentially designated MS4s located outside the urbanized areas. This regulation also affects runoff from prisons, hospitals, military bases, etc. which are located within the urban areas.

The Phase II Final Rule, published in the Federal Register on December 8, 1999, expanded the stormwater permit program to include stormwater discharges from certain regulated small MS4s and construction activity that disturbs between 1 and 5 acres of land. On January 8, 2003, the DEC finalized two-new permits for stormwater discharges in NYS as required by the Federal EPA; the MS4 and construction permits.

Phase II represents an expansion upon the requirements from Phase I which regulated construction activity disturbing five or more acres of land.

* Please note that any blue links on the web page, represent definition links and any green links, represent links to other webpages.