Knights Landing

Yolo County is a population ~217,000 county in the southern Sacramento Valley directly west of the Sacramento River from Sacramento County, with Solano County (south), Napa / Lake / Colusa Counties (west, across the Vaca Mountains / Coast Range), and Sutter County (north, across the Sutter Bypass). The county is overwhelmingly agricultural by area (Yolo is one of California's top-producing counties for tomatoes, rice, sunflowers, alfalfa, almonds, walnuts, and wine grapes) but its population is concentrated in four incorporated cities along the Sacramento River / Yolo Bypass eastern periphery: Davis (~70,000, home of UC Davis with ~40,000 students plus faculty / staff and a particularly housing-pressured market), Woodland (~62,000, the county seat, in central-eastern Yolo on Cache Creek), West Sacramento (~55,000, on the west bank of the Sacramento River directly across from downtown Sacramento, a former unincorporated industrial / port community incorporated 1987), and Winters (~7,500, on Putah Creek at the foot of the Vaca Mountains / Berryessa Reservoir). Substantial unincorporated population in Esparto (~3,300, on Cache Creek), Capay Valley (a small AVA wine region in the Capay Valley along Cache Creek upstream of Esparto), Madison, Knights Landing (on the Sacramento River in northern Yolo), Clarksburg (on the Sacramento River in southern Yolo, a small AVA wine region), Yolo (the unincorporated community), Brooks, Rumsey, Guinda, Dunnigan (north along I-5), and Zamora. The Board of Supervisors administers ADUs in unincorporated areas under Cal. Gov. Code Sec. 65852.2 / 65852.22 via the County Department of Community Services. The county is a member of the Sacramento Area Council of Governments (SACOG) and is subject to RHNA 6th-cycle (2021-2029) housing allocations administered through the Sacramento Metropolitan Transportation Plan / SACOG Sustainable Communities Strategy. Yolo is among the most aggressive Williamson Act jurisdictions in California (~85% of unincorporated parcel area is under contract or in a Farmland Security Zone). UC Davis exerts a defining influence on Davis and surrounding unincorporated lands; the Davis housing market is among the most expensive in the Sacramento metro area on a per-square-foot basis.

• Yolo County Code Title 8 (Land Development), ADU/JADU provisions
• Cal. Gov't Code Sec. 65852.2 (Accessory Dwelling Units)
• Cal. Gov't Code Sec. 65852.22 (Junior Accessory Dwelling Units)
• California Land Conservation Act of 1965 (Williamson Act) and Farmland Security Zone (Sec. 51296)
• Sacramento-San Joaquin Valley 200-Year Flood Protection (SB 5 / SB 1278)
• Yolo Habitat Conservation Plan / Natural Community Conservation Plan (Yolo HCP/NCCP)

State-floor overlay: California state ADU preemption applies in full to unincorporated Yolo County. AB 1033 condo-conversion election: not adopted as of April 2026. AB 976 prohibits owner-occupancy mandates on detached ADUs. AB 2533 unpermitted-ADU amnesty applies. SB 9 urban lot-split provisions apply only within incorporated cities (Davis, Woodland, West Sacramento, Winters); they do not apply in unincorporated parcels which are zoned A-G / A-N (agricultural) for the bulk of the county. HCD oversight applies to ordinance amendments per Sec. 65852.2(h); Yolo's housing element compliance has been routine. The Sacramento-San Joaquin Valley 200-year flood-protection findings (SB 5 / SB 1278 implementation in Cal. Gov. Code Sec. 65302.9) apply to new urban-level development in the bulk of the county. Davis has been an active SB 9 / SB 10 jurisdiction for urban-fringe ADU-friendly redevelopment, but state SB 9 lot-split does not reach unincorporated Yolo.

Yolo County overlays of consequence: (1) extensive Williamson Act / Farmland Security Zone agricultural preserves covering ~85% of unincorporated parcel area; (2) the Yolo Bypass designated flood overflow corridor occupying the eastern county; (3) FEMA SFHA along the Sacramento River, Yolo Bypass, Cache Creek, Putah Creek, and Willow Slough; (4) SB 5 / SB 1278 200-year flood-protection requirements; (5) the Yolo Habitat Conservation Plan / NCCP covering ~570,000 acres; (6) CAL FIRE SRA Very High FHSZ in the Vaca Mountains / Capay Hills / Berryessa periphery; (7) the Yocha Dehe Wintun Nation federally-recognized rancheria at Brooks and Cache Creek Casino Resort; (8) the Sacramento-San Joaquin Delta Plan in Clarksburg / southern Yolo; (9) UC Davis institutional jurisdiction; and (10) SACOG / RHNA 6th-cycle housing allocations.

• Williamson Act / Farmland Security Zone agricultural preserves
• Yolo Bypass designated flood overflow corridor
• FEMA SFHA - Sacramento River, Yolo Bypass, Cache Creek, Putah Creek, Willow Slough
• Yolo Habitat Conservation Plan / Natural Community Conservation Plan (Yolo HCP/NCCP)
• CAL FIRE State Responsibility Area / Vaca Mountains / Capay Hills / Berryessa Very High FHSZ
• Yocha Dehe Wintun Nation rancheria at Brooks / Cache Creek
• Sacramento-San Joaquin Delta Plan / Clarksburg Delta periphery
• UC Davis institutional / agricultural-research property
• SACOG / RHNA 6th Cycle (Sacramento Region Sustainable Communities Strategy)

Yolo County Department of Community Services (Planning Division and Building Division) issues ADU permits for unincorporated parcels including Esparto, Capay Valley, Madison, Knights Landing, Clarksburg, Yolo (community), Brooks, Rumsey, Guinda, Dunnigan, and Zamora. Practical permitting frictions: dominant Williamson Act / Farmland Security Zone agricultural preserves covering ~85% of unincorporated parcel area; the Yolo Bypass (a designated flood overflow corridor of the Sacramento River Flood Control Project) occupying the eastern county between Davis / West Sacramento and the Sacramento River; FEMA SFHA along the Sacramento River, Yolo Bypass, Cache Creek, Putah Creek, and Willow Slough; SB 5 / SB 1278 200-year flood-protection findings applicable to new urban-level development; the Yolo Habitat Conservation Plan / NCCP covering ~24 species across ~570,000 acres; CAL FIRE State Responsibility Area in the Vaca Mountains / Capay Hills (Very High FHSZ in upper Capay Valley, Rumsey, Guinda, and the Berryessa periphery); the Sacramento-San Joaquin Delta Plan jurisdiction in the Clarksburg / southern Yolo Delta periphery; UC Davis institutional jurisdiction for parcels within the campus footprint or research-property easements (UC Davis is the largest UC campus by acreage at ~5,300 acres); the Yocha Dehe Wintun Nation federally-recognized rancheria at Brooks (the Cache Creek Casino Resort, the largest single private employer in Yolo County); SACOG / RHNA 6th-cycle housing allocations; and the Sacramento Area Air Quality Management District jurisdiction.