Description
Sea level rise and increased flooding due to precipitation changes represent a risk to on-site wastewater infrastructure in unincorporated King County. Building from and expanding sea level rise work completed in 2025 for Vashon and Maury Island, the County will identify where sea level rise and flooding are most likely to impact on-site sewage systems on Vashon-Maury Island and unincorporated areas in the lower Duwamish Valley adjoining South Park, and where the equity related needs for addressing those impacts are greatest. King County will then work with partners to secure funding to improve wastewater infrastructure in high-risk areas.