Spokane Valley, WA Environmental Rules: Stormwater Management (2026)

The City's stormwater program runs on two tracks. 67 RCW. 150 SVMC, defines "regulated activities" that trigger City review before work begins: grading over 500 cubic yards, new construction or added impervious surface exceeding 5,000 square feet (incremental-stage projects are measured at full build-out), land disturbance of one acre or more, subdivision or binding-site-plan actions, and drywells or other UIC wells under WAC 173-218. The City adopts the Spokane Regional Stormwater Manual by reference as its technical standard for best management practices. Applicants submit an erosion and sediment control plan, and the city manager or designee can attach conditions of approval addressing drainage facilities, slope stabilization, and protection of adjacent and downstream property.

A deviation from the chapter's requirements is available only if the applicant shows sound engineering justification, no undue harm to downstream properties, and no conflict with an existing condition of approval; deviations must be secured before construction plans are accepted. Stormwater facilities must be completed and certified by the proponent's engineer before final plat or certificate of occupancy, though a performance surety can substitute when completion is impractical for a construction season, with a two-year warranty surety required after acceptance. The city manager or designee may inspect both public and private property to verify facilities are built and maintained to standard, and can require annual third-party certification of maintenance on private stormwater facilities.