Solano County, CA Landscaping Rules: Native Plants (2026)

There is no Solano County ordinance requiring homeowners to plant California native species, and no countywide prohibition on lawns or non-native ornamentals on private property. Instead, native and low-water planting is driven economically and technically by the County's adopted Model Water Efficient Landscape Ordinance (Solano County Code Chapter 13.5, incorporating California Code of Regulations Title 23, Sections 490 et seq.). For landscape projects meeting the applicability thresholds (new 500+ sq ft, rehabilitated 2,500+ sq ft), MWELO establishes a Maximum Applied Water Allowance based on a plant-factor and reference evapotranspiration calculation; because native, drought-tolerant, and climate-adapted plants carry low plant-factor values, designers typically must use them - and limit high-water turf - to keep the project within budget. MWELO also requires grouping plants by water need (hydrozones) and a minimum three inches of mulch. The 2008 Solano County General Plan separately encourages retention of native oak woodland, riparian, and grassland vegetation as resource-conservation policy. For small residential plantings below the WELO thresholds, plant choice is entirely the owner's preference; native-plant landscaping is supported and rebated by regional water agencies but not legally required.