Santa Cruz County, CA Accessory Structures: ADU Rules (2026)
ADU rules in Santa Cruz County, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Governing code
- County Code 13.10.681 + CA Gov. Code 66310+
- Max detached size
- 850-1,000 sq ft (<1 acre); 1,200 sq ft (1+ acre)
- Side/rear setback
- 4 feet for new construction
- Parking
- 1 space for new construction; exemptions near transit/historic/car-share
- Owner-occupancy
- Required for JADU; not required for standard ADU
- Coastal Zone
- Added permit review; no parking exemptions in designated areas
Summary
Unincorporated Santa Cruz County allows accessory dwelling units ministerially under County Code 13.10.681 and California's state ADU law. Detached ADUs can be 850-1,200 sq ft, with 4-foot side/rear setbacks and limited parking. Coastal Zone projects may face added review, and certain coastal areas require a replacement parking space.
Areas zoned for single-family dwelling residential use may potentially have up to four ADUs, including one detached ADU no more than 800 square feet with minimum 4-foot side and rear setbacks and height no more than 16 feet, 18 feet if near transit, or 20 feet if roof pitch aligns with primary dwelling unit.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 5004302; v11 updated 2026-05-19; through 05-19-2026).
Full Breakdown
681, implemented consistent with California's ADU law (Gov. Code 66310-66342), which preempts overly restrictive local rules. The County's published ADU/JADU Development Standards set a minimum unit size of 150 sq ft. Detached ADUs may be up to 850 sq ft (studio/1-bedroom) or 1,000 sq ft (2+ bedrooms) on parcels under one acre, and up to 1,200 sq ft on parcels of one acre or more. Conversion ADUs (within existing space) and junior ADUs (JADUs, 150-500 sq ft) are also allowed. In single-family zones the County permits up to four ADUs total on a lot, combining the state-mandated combinations under Gov.
Code 66323. Side and rear setbacks for new construction are 4 feet; detached ADUs inside the Urban Services Line are limited to 16 feet in height (24 feet over a garage). One parking space is generally required for new-construction ADUs, with exemptions near transit, on historic sites, or near car-share. JADUs require owner-occupancy of the property; standard ADUs do not. ADUs cannot be used as short-term rentals (30-day minimum lease). In the Coastal Zone additional building-permit review may apply, and designated coastal areas (such as Live Oak and Seacliff/Aptos/La Selva) require one parking space with no exemptions and replacement parking when existing spaces are removed.
Violations & Fines
Building an ADU without required ministerial approval, exceeding size or height limits, renting an ADU for under 30 days (prohibited short-term rental), or removing required coastal-area parking without replacement can trigger code-enforcement action, stop-work orders, permit denial, and required corrections through the County Community Development and Infrastructure Department.
Frequently Asked Questions
How big can an ADU be in unincorporated Santa Cruz County?
Does the Coastal Zone change the ADU rules?
Sources & Official References
Other rules in Santa Cruz County
How Santa Cruz County compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Santa Cruz County to another location·View the California accessory structures overview
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