Stormwater

Why does stormwater runoff matter?

As the population grows in Washington, urban development increases. This means more people, more developed land, and an increase in stormwater runoff and pollution to Washington's waters.

Unmanaged stormwater runoff can:

• Damage salmon habitat.
• Contribute to flooding and drought.
• Contaminate swimming areas.
• Pollute shellfish beds.
• Contaminate the groundwater you drink.
• Degrade water quality.

What are we doing about it?

We issue permits under federal and state laws to control surface and groundwater pollution from runoff. The most-populated cities and counties, as well as industrial sites, construction sites, and many businesses have stormwater permits.

We also:

• Provide guidance and technical assistance on how to comply with permit requirements.
• Monitor results to show how well we are doing.
• Enforce as a last resort when pollution limits in permits are not met. Penalty fines that we collect go to the state’s general fund or to dedicated pollution prevention accounts. 
• Provide funding for stormwater improvement projects.

What types of permits are there?

The federal Clean Water Act's National Pollutant Discharge Elimination System (NPDES) has various permitting requirements based on different types of pollution discharges.

Both NPDES and State Waste Discharge stormwater general permits aim to control pollution discharges to water. For more information, see stormwater general permits.

Our permits include:

• Construction Permit
• Industrial Permit
• Municipal Permits
  • Phase I
  • Phase II: Western and Eastern Washington
  • WSDOT municipal permit
• Sand and Gravel Permit
• Boatyard Permit

Stormwater guidance & databases

Go to our stormwater permittee guidance page to learn more about applying, changing, implementing, and complying with your stormwater permit.

Stormwater databases

• Permit and Reporting Information System (PARIS) contains stormwater compliance monitoring information.
• Environmental Information Management (EIM) contains stormwater characterization data.

Stormwater monitoring

Are we successful at preventing or reducing pollution from stormwater runoff? Check out the Stormwater Action Monitoring (SAM) program and other results on the stormwater monitoring page.