Ecology Construction Stormwater Permit

The Cities and County have adopted ordinances to regulate stormwater runoff control requirements for construction sites that meet a size threshold. In addition, construction site operators may be required to apply for the Department of Ecology Stormwater Construction Permit. The following provides contractors with information to determine whether they need Ecology’s permit and how to apply.

Which Construction Sites Need To Apply For A Permit?

Construction activities that require this permit are any land disturbing activities such as clearing, grading, excavating, and/or demolition that:

1. Disturb one or more acres of land area; OR

2. Are “part of a larger common plan of development or sale” that will ultimately disturb one or more acres of land; AND

3. Discharge stormwater from the site into state surface water(s) or into storm drainage systems, which discharge to state surface waters. Ecology can also require a permit for any size construction site, if it determines the site is a significant contributor of pollutants to waters of the state.

Who Needs To Apply?

The operator of the construction site must apply for permit coverage. The operator can be either the party with operational control over construction plans and specifications or the party in charge of day-to-day activities related to the Stormwater Pollution Prevention Plan (SWPPP). The operator, also known as the permittee, is responsible for applying and following the terms of the Construction Stormwater General Permit. All municipal governments must apply for permit coverage for construction projects with one acre or more of disturbed area that discharge stormwater to state waters.

What Does The Permit Require?

  • Apply for Coverage
  • Develop and Use a Stormwater Pollution Prevention Plan
  • Pay Permit Fees
  • Monitor Stormwater and Inspect Best Management Practices
  • Record and Report Results
  • Terminate the Permit

For more information on this process, click here

Ecology has published a guidance document to help navigate the requirements of the permit. For more information, follow the link to view online:


City of Asotin County of Asotin City of Clarkston