Ecology requires construction site operators to have Construction Stormwater General Permit coverage if they are engaged in clearing, grading, and excavating activities that disturb one or more acres and discharge stormwater to surface waters of the state.
The permit is also required if clearing, grading or excavating activities disturb an area smaller than 1 acre if it is part of a "larger common plan of development or sale" that will disturb 1 acre or more and discharge stormwater to surface waters of the state or a conveyance system that drains to surface waters of the state.
"Surface waters of the state" are broadly defined by state law and include lakes, rivers, ponds, streams, inland waters, salt waters and all other surface waters and watercourses within the jurisdiction of the State of Washington.
In addition to these permit triggers, Ecology reserves the right to require permit coverage at a construction site of any size, if Ecology believes that the site may be a significant contributor of pollutants to surface waters of the State of Washington or reasonably expects the site to cause a violation of any water quality standards.
For more information, please go to the Construction Stormwater General Permit homepage.