Four jurisdictions, one coastline, four different rulebooks on top of the same state law. If you own or are buying a lot in the City of Santa Barbara, unincorporated Santa Barbara County, Goleta, or Carpinteria and you want an accessory dwelling unit, the state floor is identical — but the local overlays, coastal-zone permitting, height rules, and fees are not. I'm Brian Cooper, REALTOR® at eXp Realty (DRE# 01434286). Below is the side-by-side comparison I could never find in one place, so I built it.
Quick answer
Every ADU in Santa Barbara County starts from the same statewide baseline. What differs is the local ordinance layered on top and — the big one along this coast — whether your parcel sits inside the Coastal Zone. A lot two blocks apart can face very different permitting simply because one is inland and one is coastal. Use the comparison table below as your starting map, then verify the specifics for your exact address, because coastal boundaries, hillside overlays, and HOA architectural review can all change the answer.
The California ADU baseline (Gov Code 66310-66342)
In 2024, SB 477 reorganized California's scattered ADU statutes into a single block, Government Code sections 66310 through 66342. The substance carried over from the old sections 65852.2 (ADUs) and 65852.22 (JADUs), but the citations changed, so older ordinances and web pages that reference "65852.2" are pointing at renumbered law. Every city and county must administer ADUs at or above this floor; a local ordinance that falls below it or conflicts with it is void by operation of law until corrected.
The mandatory state floor as of 2026 includes:
- Detached ADU: up to 1,200 sq ft (a jurisdiction may allow larger).
- Attached ADU: 50% of the primary dwelling's living area, subject to the ordinance's cap.
- JADU: up to 500 sq ft, within the existing single-family footprint, with an efficiency kitchen and owner-occupancy of either unit.
- Setbacks: 4-foot minimum side and rear for new detached ADUs; no setback required for conversions of existing space.
- Minimum allowance: jurisdictions must permit at least an 850 sq ft studio or 1,000 sq ft one-bedroom regardless of other limits.
- Owner-occupancy: not required for ADUs permitted on or after January 1, 2020 (made permanent by AB 976, 2023).
- Review: 60-day ministerial (by-right) review of a complete application — no discretionary hearing.
Recent statewide changes worth knowing: SB 1211 (effective January 1, 2025) allows up to eight detached ADUs on lots with existing multifamily dwellings and bars replacement-parking mandates when a covered space is removed. AB 2533 (2025) expanded the amnesty path for unpermitted ADUs and JADUs built before January 1, 2020. AB 1332 required every jurisdiction to stand up a preapproved-plan program by January 1, 2025. And AB 1033 (2023) created an optional, opt-in framework for selling an ADU as a condominium separate from the main house.
City of Santa Barbara
The City of Santa Barbara permits ADUs and JADUs ministerially on qualifying single-family and multifamily lots, administered through its Community Development Department and its published Accessory Dwelling Unit Guide. City standards track the state floor with local detailing: detached ADUs up to 1,200 sq ft, attached ADUs limited to 50% of the primary dwelling (commonly capped around 1,000 sq ft), and a minimum ADU size of 150 sq ft. Side and rear setbacks are 4 feet.
The city's distinctive rules concern front-yard placement and its coastal overlay. A new ADU in the front-yard area generally requires a 20-foot front setback with screening from the street, unless it is a single-story unit under about 17 feet or built over a garage. Parcels inside the city's Coastal Zone fall under the S-D-3 Coastal Overlay and must be consistent with the city's certified Local Coastal Program, which can trigger a Coastal Development Permit. The city also runs a preapproved ADU plan program to speed review. Target review is 60 days ministerial, with most projects finishing within three to four months of a complete submittal.
Unincorporated Santa Barbara County
Outside the incorporated cities, ADUs fall under the County of Santa Barbara's Planning and Development Department. The County administers ADUs under two parallel codes: the Land Use and Development Code for inland areas and the Coastal Zoning Ordinance for parcels within the Coastal Zone. This split is the single most important thing for County buyers to understand — the substantive ADU standards are similar, but coastal parcels add Local Coastal Program consistency review and, frequently, a Coastal Development Permit.
County standards follow the state floor: detached ADUs up to 1,200 sq ft, attached up to 50% of the primary residence (to 1,200 sq ft), JADUs to 500 sq ft, and 4-foot side/rear setbacks for new detached units. ADUs under 800 sq ft benefit from the most lenient development standards. A recent County ordinance update also expanded where ADUs are allowed, including certain agricultural preserve parcels. Because unincorporated communities such as Montecito, Summerland, Hope Ranch, and the Santa Ynez Valley each carry their own overlays and, in some cases, community plans, confirm the exact standard for your address with County Planning.
Goleta
The City of Goleta permits ADUs in its R-1, R-2, PRD, RM, and mixed-use zones on lots with a proposed or existing single-family or multifamily dwelling, administered under its zoning code (Chapter 17.41 for specific-use standards). Goleta revised its ADU ordinance to match state law and, like everyone else, imposes no owner-occupancy requirement on ADUs while requiring it (with a deed restriction) for JADUs on single-family lots.
Goleta's homeowner-friendly features are on the fee side. Consistent with state law, the city waives certain development impact fees for ADUs under 750 sq ft; for ADUs of 750 sq ft or more, fees are charged proportionally to the primary dwelling's size (or average unit size on multifamily). Goleta also operates a preapproved ADU plan program under AB 1332, with a published planning-review-and-Design-Review-Board acceptance fee. Fee schedules change every fiscal year — confirm the current numbers with the City of Goleta before budgeting.
Carpinteria
Carpinteria adopted its ADU ordinance (No. 758) in early 2023 and, at a March 2025 Planning Commission action, amended it to fold in recent state-law changes — notably the higher ADU height allowances and the prohibition on front-setback limits. Under the amended ordinance, ADUs may be built taller than the old ceiling, in some cases up to the height of the primary dwelling, subject to the applicable standards.
The coastal dimension is central in Carpinteria: much of the city sits within the Coastal Zone. Even the city's preapproved prototype ADU plans typically still require a Coastal Development Permit in addition to a building permit before construction. Carpinteria has prepared stock detached-ADU prototype plans in PDF form to streamline design, but the coastal permitting step remains. If you are buying in Carpinteria with an ADU in mind, budget time for the CDP and confirm the current process with the city's Community Development Department.
Side-by-side ADU comparison (2026)
The comparison below summarizes how the four jurisdictions stack up on the standards buyers ask about most. All four are bound by the same statewide floor; the table highlights where the local overlay matters. Verify any single line with the jurisdiction before relying on it.
| Rule | City of Santa Barbara | Unincorp. County | Goleta | Carpinteria |
|---|---|---|---|---|
| Governing code | City ADU ordinance + S-D-3 coastal overlay | Land Use & Development Code (inland) / Coastal Zoning Ordinance | City zoning code (incl. Ch. 17.41) | ADU Ord. No. 758, amended 2025 |
| Max detached ADU | 1,200 sq ft | 1,200 sq ft | 1,200 sq ft | 1,200 sq ft |
| Attached ADU cap | 50% of primary (~1,000 sq ft) | 50% of primary (to 1,200) | 50% of primary | 50% of primary |
| Side / rear setback | 4 ft | 4 ft | 4 ft | 4 ft |
| Front-yard rule | 20 ft (with exceptions) | Per zone / community plan | Per zone | No front-setback limit (state) |
| Owner-occupancy (ADU) | No | No | No | No |
| Owner-occupancy (JADU) | Yes | Yes | Yes | Yes |
| Coastal Development Permit | If in Coastal Zone (S-D-3) | If in Coastal Zone | Limited coastal area | Common — much of city is coastal |
| Preapproved-plan program | Yes | Program in place | Yes (fee applies) | Yes (prototype plans) |
| ADU fee relief < 750 sq ft | Per state law | Per state law | Certain fees waived | Per state law |
The pattern is clear: the size and setback numbers barely move across jurisdictions because the state floor controls them. Where you actually feel the difference is coastal permitting (a real cost and timeline factor in Carpinteria and coastal County parcels), front-yard placement in the City of Santa Barbara, and fee treatment in Goleta.
JADUs and the coastal wrinkle
A Junior ADU is the smaller sibling — up to 500 sq ft, carved entirely from the existing single-family footprint, with an efficiency kitchen and a required owner-occupancy deed restriction. JADUs are cheaper and faster than detached ADUs, but the owner-occupancy requirement and size cap limit them to family or modest-rental use, and AB 1033 condo sale does not apply to them. In the coastal zone, converting interior space to a JADU can still implicate the Local Coastal Program, so do not assume a JADU escapes coastal review.
What this means if you're buying
ADU potential is now a genuine value driver along the South Coast, and it is one of the least-understood parts of a purchase. Before you write an offer with an ADU plan in mind, I pull the parcel's zoning, confirm whether it is inland or coastal, check for hillside or community-plan overlays and any HOA architectural review, and flag whether a Coastal Development Permit is likely. That five-minute check has saved my clients from paying an ADU premium for a lot where the ADU would be far harder to build than the listing implied.
Frequently asked questions
Do all four jurisdictions follow the same state ADU baseline?
Yes. All are bound by California's statewide floor at Government Code sections 66310-66342 (formerly 65852.2/65852.22). Local ordinances can add standards above the floor but cannot prohibit ADUs on most single-family lots or drop below the minimums. Confirm current rules with the jurisdiction before you design.
Is owner-occupancy required to build an ADU in Santa Barbara County?
No for ADUs — AB 976 (2023) made the no-owner-occupancy rule permanent for units permitted on or after January 1, 2020, across all four jurisdictions. JADUs still require owner-occupancy with a recorded deed restriction.
Do I need a Coastal Development Permit for an ADU?
It depends on the parcel. Coastal-Zone parcels in the City of Santa Barbara, unincorporated County, and Carpinteria must be consistent with the certified Local Coastal Program and often require a CDP — even for preapproved prototype plans. Verify coastal status and permit requirements with the jurisdiction for your specific address.
What is the largest detached ADU I can build?
The statewide ceiling is 1,200 sq ft detached, and all four jurisdictions follow it. Attached ADUs are capped at 50% of the primary dwelling, and JADUs at 500 sq ft. Jurisdictions must still allow at least an 850 sq ft studio or 1,000 sq ft one-bedroom.
Can I build multiple ADUs on a multifamily lot?
SB 1211 (effective January 1, 2025) allows up to eight detached ADUs on lots with existing multifamily dwellings, capped at the number of existing units, plus conversions. Confirm how your jurisdiction applies it to your parcel.
Does Goleta waive ADU fees?
Goleta waives certain development impact fees for ADUs under 750 sq ft and charges larger ADUs proportionally. Fee schedules change annually; confirm current fees with the City of Goleta.
Can I sell my ADU separately from the main house?
Only where the jurisdiction has opted in to AB 1033. Adoption is local and optional; as of 2026, do not assume any of these four jurisdictions has opted in. Confirm current opt-in status with planning.
Related on this site
- When You Need a Coastal Development Permit in Santa Barbara
- Santa Barbara Short-Term Rental Ordinance (2026)
- Carpinteria Vacation-Rental Permits
- Santa Barbara Rent Freeze — Landlord Impact
- Prop 19: Ventura-to-Santa-Barbara Base-Year Transfer
- Santa Barbara Real Estate
- Priced Out of Santa Barbara? Ventura County Guide
