San Mateo County, CA Landscaping Rules: Native Plants (2026)

There is no general requirement that homeowners in unincorporated San Mateo County plant California natives, but the County strongly encourages them and channels new and rehabilitated landscapes toward low-water, climate-adapted species through its Water Efficient Landscape Ordinance (WELO), which requires most planted area to meet a WUCOLS plant factor of 0.3 - a standard easily met by California natives. The San Mateo Countywide Water Pollution Prevention Program (Flows To Bay) highlights native plants for water conservation, reduced pesticide use, low maintenance, and pollinator support, noting that monarch butterflies depend on native milkweed and recommending species such as purple needlegrass, hummingbird sage, coyote mint, and miniature lupine (with selection tools like CalScape). Financial incentives reinforce the message: BAWSCA's Lawn Be Gone (lawn replacement) rebate pays up to $4 per square foot to convert turf to drought-tolerant plantings, with an additional $300 rebate for adding a rain garden. These are voluntary, rebate-driven programs administered with water agencies and the County Office of Sustainability, plus free landscaping classes through BAWSCA and UC Master Gardeners. Note that native plantings still interact with defensible space and tree rules - removing protected native oaks or madrones to landscape still requires a tree permit (see Tree Removal).