Seattle

Clark County to Launch Major Stormwater Filtration System on NW 99th Street, Traffic Delays Expected

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Published on July 06, 2025
Clark County to Launch Major Stormwater Filtration System on NW 99th Street, Traffic Delays ExpectedSource: Google Street View

Clark County will begin a stormwater filtration project in July to treat runoff from about five acres of paved surfaces. The work will occur along Northwest 99th Street, Northwest 9th Avenue, and nearby areas. The project includes a main filtration vault and three stormwater filter catch basins, according to the Clark County.

Construction along Northwest 99th Street may cause delays, but all travel lanes will stay open. Clark County Public Works advises drivers "to slow down, pay attention and be patient in work zones."

Clark County Public Works will post construction updates for the water quality improvement project on its website. Residents can also find information about county projects, road and park closures, and community events by following Public Works on X, Facebook, Instagram, and Nextdoor.

Seattle-Transportation & Infrastructure