Stormwater Source Control

The Stormwater Source Control is a new program the City of Mercer Island is implementing to stop pollution before it enters Lake Washington.

Purpose of Stormwater Source Control

Stormwater Source Control aims to address non-point source pollutants such as fertilizers, oil, grease, washwater, etc., that originate from business / business site activities. This polluted stormwater, accumulated from combined runoff from commercial, industrial, or other activities, then collects and discharges to receiving waterways and eventually into Lake Washington.

Polluted stormwater has been shown to have negative impacts on orcas, salmon, and all species that depend on healthy water quality. Preventing pollution at the source is a critical step that must be taken to protect our receiving waters.

What does this program entail?

The Stormwater Source Control program aims to stop stormwater pollution though inspections that will provide educational and technical assistance to businesses to encourage best stormwater management practices.

Inspectors will work with businesses to reach compliance by addressing areas of improvement. If inspectors find facilities failed to meet Stormwater Source Control program requirements, a corrective action letter will be sent.

Businesses will be given a period to make necessary changes requested in the corrective action letter. The inspector will work with businesses to meet guidelines but if the inspector finds minimal effort to meet requirements, an enforcement action will be taken through the Maintenance and Inspection Ordinance (MICC 15.09.070).

Inspections aim to help businesses implement best management practices to reduce stormwater pollution for a healthier environment.

What to Expect During an Inspection

During a typical 1-hour inspection, inspectors will do the following:

Observe the facility during normal business operations
Visit loading sites, storage, and process areas
Check site storm drains, which drain directly into Lake Washington, for signs of pollution
Make recommendations to reach compliance