Stormwater runoff is rain that runs off hard surfaces, rooftops, streets, parking lots, and landscaped areas. As water runs off these surfaces, it can pick up pollutants such as oils, dirt, and fertilizers. Polluted stormwater runoff is a leading contributor to water pollution in the Puget Sound region.
Runoff can also cause and contribute to flooding. When runoff is uncontrolled, it could result in the destruction of property, harm to fish and wildlife, damage to aquatic habitats, loss in aesthetic values, and cause threats to public health due to contaminated food, drinking water supplies, and recreational waterways.
Snohomish County is committed to complying with federal and state requirements to provide effective and efficient stormwater management in our community. As part of our work, we maintain stormwater regulations that guide new development and redevelopment to minimize pollution and harmful effects of stormwater.
Please visit the Stormwater and Drainage Regulations webpage for more information on the permitting process and links to associated checklists and assistance bulletins.
The County’s current stormwater and drainage requirements are found in: