San Diego County's green streets filter stormwater inland, upstream of the beaches
Oct. 23, 2026 — San Diego County has 48 Green Streets projects, 10 completed and 38 in planning, design or construction, the County said Oct. 22. It described them as natural filters that slow stormwater and capture trash, bacteria, nitrogen and phosphorus before runoff reaches creeks and the ocean.
The County's project pages list 14 of them: 10 completed, one under construction and three upcoming. They sit in unincorporated communities from Rainbow and Fallbrook in the north to Lakeside and Spring Valley in the east. The 13 that TDD could place lie about 10 to 30 km inland, measured from the streets the pages name. Their watersheds run to the coast, from the Santa Margarita in the north to the Sweetwater, which drains to San Diego Bay.
The largest completed project, in Rainbow, uses about 3,400 feet of underground wetland channels to filter runoff from nearly 345 acres in the Santa Margarita watershed, and added 500 feet of sidewalk, two ADA ramps and 27 rebuilt driveways, the County said. In Lakeside, the Los Coches Road project, completed in fall 2024, sends about 1.3 million gallons a year of dry-weather runoff to the East County Advanced Water Purification project, which treats water to drinking standards, its page says.
The wall: The County's pages do not list the other 34 projects in its count of 48. The release did not say how much pollution the projects remove or whether water quality at the beaches has changed. Distances are approximate, measured from street locations.
Tier: Confirmed (based on the County's release and its Green Infrastructure project pages, read Oct. 23)
Sources
- County of San Diego News Center, County Green Streets Help Filter El Niño Stormwater (Oct. 22, 2026)
- County of San Diego DPW, Green Infrastructure Projects (read Oct. 23, 2026)
- County of San Diego DPW, Rainbow Water Quality Project (read Oct. 23, 2026)
- County of San Diego DPW, Los Coches Road Dry Weather Diversion Pilot Project (read Oct. 23, 2026)
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