NPDES Permit Program

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Protecting our Waters from Pollutants

Stormwater runoff is generated when precipitation from rain and snow melt flows over impervious surfaces – such as paved streets, parking lots, and building rooftops – and doesn’t seep into the ground. As the runoff moves, it accumulates debris, chemicals, sediment or other pollutants that could adversely affect water quality if the runoff discharged is left untreated. Most stormwater discharges are considered point sources and require coverage under a National Pollutant Discharge Elimination System (NPDES) permit.

During the early 1990’s, the Environmental Protection Agency (EPA) Created the NPDES to address the high levels of pollutants entering our nation’s waters. The permitting system requires that waste producers having direct discharges to surfaces waters undergo an extensive permitting process to demonstrate the impacts of the respective industrial operation, and their need to be minimized. Since the inception of the program, NPDES has been expanded to include stormwater issues.

2013-2018 Western Washington Phase II Municipal Stormwater Permit - NPDES

npdes-logoThe NPDES permit program is a requirement of the federal Clean Water Act, which is intended to protect and restore waters for “fishable, swimmable” uses. The federal Environmental Protection Agency (EPA) has delegated permit authority to state environmental agencies. In Washington, the NPDES-delegated permit authority is the Washington State Department of Ecology (DOE).

City of Tumwater is considered a Phase II community because of its municipality population size. Phase II permits cover urbanized areas of the county where the population is greater than 1,000 people per square mile. The permit allows municipalities to discharge stormwater runoff from municipal drainage systems into the State’s water bodies (i.e., streams, rivers, lakes, wetlands, etc.) as long as municipalities implement programs to protect water quality by reducing the discharge of “non-point source” pollutants to the “maximum extent practicable” (MEP) through application of Permit-specified “best management practices” (BMPs). 

The City of Tumwater’s current Stormwater Permit was issued by the Washington State Department of Ecology in August of 2012, and will expire on July 31, 2018.

Stormwater Management Plan

The Department of Ecology (DOE) has the delegated responsibility to implement NPDES requirements within the State of Washington.  Under the permit, affected jurisdictions are required to develop and implement a comprehensive Stormwater Management Program (SWMP) that includes, in general, the following components:

  • Public Education and Outreach
  • Public Involvement and Participation
  • Illicit Discharge Detection and Elimination
  • Controlling Runoff from New Development, Redevelopment and Construction Sites
  • Pollution Prevention and Operations and Maintenance for Municipal Operations

NPDES Compliance Reports

 NPDES Management Plan Updates  Annual NPDES Reports
 2017 Stormwater Management Plan Update pdf-icon-sm  2017 NPDES Annual Report pdf-icon-sm
 2016 Stormwater Management Plan Update pdf-icon-sm  2016 NPDES Annual Report pdf-icon-sm
 2015 Stormwater Management Plan Update pdf-icon-sm  2015 NPDES Annual Report pdf-icon-sm
   2014 NPDES Annual Report pdf-icon-sm


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