Auburn, WA Environmental Rules: Stormwater Management (2026)

Auburn's surface water management program implements the Western Washington Phase II Municipal Stormwater NPDES Permit issued by the Washington Department of Ecology and is codified in ACC Title 13 utilities and surface water sections of Title 17. New development and redevelopment that creates or replaces thresholds of impervious surface must meet the most recent Department of Ecology Stormwater Management Manual for Western Washington, including minimum requirements for source control, runoff treatment, flow control, and low impact development (LID). Typical triggers include adding 2,000 square feet of impervious surface, disturbing 7,000 square feet of land, or creating new pollution-generating impervious surface. Detention vaults, rain gardens, permeable pavement, and bioswales are common compliance features. Auburn enforces illicit discharge rules that prohibit non-stormwater flows to the storm system, including car wash water, paint rinse, and yard chemicals. Spills and illegal dumping should be reported to the Auburn Storm Drainage Utility at (253) 931-3048. Auburn drains to the Green River and its tributaries including Mill Creek, Bowman Creek, and White River, which receive additional water-quality focus due to salmon habitat and downstream Muckleshoot tribal fishery interests. Annual outreach programs and car-wash kits are available for fundraiser groups.