What is the difference between the two phases of the NPDES Stormwater Program?
Phase I of the NPDES Stormwater Program was promulgated in 1990. It requires large and medium municipal separate storm sewer systems (MS4s) located in incorporated counties with a population of 100,000 or more to obtain NPDES permits. Phase II of the NPDES Stormwater Program was promulgated in 1999. It requires MS4s not regulated by Phase I, and small construction activities to obtain NPDES permits and develop comprehensive stormwater management programs that will eliminate illicit discharges to MS4s and reduce pollutants in stormwater runoff. USF is a part of the Phase II MS4 program.
