On December 8, 1999 the Environmental Protection Agency (EPA) finalized a rule that
extends the current regulations for stormwater discharges to municipal separtate storm
sewer systems (MS4s) in urban areas having populations less than 100,000 and to
construction sites between one and five acres in size. The rule (40 CFR Parts 9,
122, 123 and 124) is known as Phase II of the National Pollutant Discharge Elimination
System (NPDES) Program. It requires small MS4s that were not covered by the Phase I
program to participate in the NPDES program and obtain a storm water permit by March 10,
2003. According to the rule, the MS4s most likely affected are those municipalities
with populations of 10,000 or more and a population density of at least 1,000 per square
mile. The rule includes military bases located within Census Bureau-defined urbanized
areas.
