Introduction to Phase II Municipal Stormwater Permits
The Phase II Municipal Stormwater Permit rule extends the coverage of the National Pollutant Discharge
Elimination System (NPDES) program to certain "small" municipal separate
stormwater sewer systems (MS4s). The Washington State permits cover
certain urbanized areas of Washington State. According to the rules,
Phase II communities
are jurisdictions that:
- Own and operate a storm drain system
- Discharge to surface waters
- Are located in urbanized areas
- Have a population greater than 1,000
The Department of Ecology developed
maps of
the census urbanized areas and jurisdictional boundaries. Ecology used
these maps to identify potential Phase II jurisdictions. According to these
maps, 104 towns, cities and counties are located with urban areas, and
Ecology determined that these jurisdictions need to
apply for Phase II stormwater permit coverage.
The Phase II permit for western
Washington applies to all regulated small municipal separate storm sewer
systems. It covers at least 80 cities and 5 counties.
The Phase II permit for eastern
Washington applies to all regulated small municipal separate storm sewer
systems. It covers 20 cities and 8 counties.
