California ADU rules · Santa Cruz County
Can I Build an ADU in Santa Cruz?
Yes — you can build an ADU in Santa Cruz. California's statewide ADU law requires every city, including Santa Cruz, to approve a qualifying accessory dwelling unit by right, plus a junior ADU (JADU) on a single-family lot. What varies city to city are the local specifics below.
Can you build one?
ADUs allowed
CA state lawYes — by right
ADUs and JADUs are allowed by right in all residential and mixed-use zones; ministerial approval, no hearing.
Units on a single-family lot
CA state law1 ADU + 1 JADU
At least one ADU and one JADU per single-family lot (a conversion ADU may also be possible).
Units on a multifamily lot
CA state lawConversion ADUs (≥1, up to 25% of units) + up to 8 detached
Conversions of non-livable space (at least 1, or up to 25% of existing units) plus up to 8 detached ADUs on a lot with existing multifamily — never exceeding the number of existing units. JADUs are single-family only.
Junior ADU (JADU)
CA state lawAllowed
Up to 500 sq ft, within the walls of an existing single-family home (single-family lots only).
Size & height
Max detached ADU size
Local rule1,000 sq ft
Santa Cruz caps a detached ADU at 850 sq ft (studio/1-bedroom) or 1,000 sq ft (2+ bedrooms); up to 1,200 sq ft is allowed only where that does not exceed 10% of total lot area. The 800 sq ft by-right floor still applies regardless of these caps. Confirm the size tier against SCMC Ch. 24.16 for your bedroom count and lot size.
Max attached ADU size
CA state law50% of the primary dwelling, but ≥850 sq ft (≥1,000 sq ft for 2+ bedrooms) is always allowed
Guaranteed minimum size
CA state law800 sq ft
An 800 sq ft ADU must be allowed regardless of FAR/lot-coverage caps; a city also cannot cap an attached ADU below 850 sq ft (1,000 for 2+ bedrooms).
Max JADU size
CA state law500 sq ft
Max height
Local rule16 ft
16 ft by right; with design-review approval a detached ADU may reach 21 ft, or up to 24 ft when built above a detached garage. State transit/two-story 18-ft allowances also apply.
Setbacks
Side setback
CA state law4 ft
A city cannot require more than 4 ft side or rear setback; conversions of existing structures are exempt.
Rear setback
Local rule4 ft
4 ft rear setback for an ADU up to 16 ft tall; the rear setback increases to a minimum of 8 ft for an ADU over 16 ft. State law guarantees the 4-ft setback for the by-right 16-ft ADU.
Front setback
CA state lawNo front setback may block the mandatory 800 sq ft / 16-ft / 4-ft-setback ADU; otherwise per base zone
Separation from main house
CA state lawNone required
No statewide separation requirement between the ADU and the primary dwelling.
Parking
Parking required
CA state lawUp to 1 space
At most 1 space per ADU (or per bedroom, whichever is less) — and waived in the common cases below.
Transit parking exemption
CA state lawYes — no parking required near transit & for conversions
No parking may be required within ½ mi walking distance of transit, in a historic district, for an ADU within an existing structure, within one block of car-share, or in certain permit-parking areas.
Garage-conversion replacement parking
CA state lawNot required
When a garage/carport is demolished or converted to build an ADU, replacement parking cannot be required.
Approval, timeline & cost
Approval path
CA state lawMinisterial (by right)
No public hearing or discretionary design review for a qualifying ADU.
Approval timeline
CA state law60 days
The agency must act within 60 days of a complete application — and the ADU is deemed approved if it does not.
Owner-occupancy
CA state lawOnly for a JADU
No owner-occupancy requirement for ADUs (the prior sunset was removed). A JADU may require owner-occupancy, principally where it shares sanitation with the main house.
Impact-fee waiver
CA state lawWaived under 750 sq ft
An ADU of 750 sq ft or less pays no impact fees (the 750 sq ft threshold itself is exempt under § 66311.5); larger ADUs pay fees proportional to the primary dwelling. JADUs (≤ 500 sq ft) are exempt.
Permits required
CA state lawBuilding permit
Only a ministerial building permit — no conditional use permit or discretionary design review for a qualifying ADU.
Santa Cruz-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Coastal Zone / Local Coastal Program
Most of the city lies within the Coastal Zone. ADUs there must satisfy the city's Local Coastal Program and Coastal Act resource-protection policies in addition to state ADU law, and Coastal Zone parking (new or replacement spaces) may be required depending on the property's location — an exception to the usual no-parking rule.
Fire Hazard Severity Zones
Portions of the city's wildland-urban interface fall in elevated fire-hazard zones; ADUs there must meet local fire/building code requirements (e.g. defensible space, ignition-resistant construction). Sprinklers are not required for an ADU unless required for the primary dwelling.
Historic resources
ADUs are not prohibited on historic properties, but demolition or alteration of a designated historic structure may trigger additional review and design standards.
Santa Cruz has its own ADU chapter (Mun. Code Ch. 24.16, Part 2), not bare state law. Detached ADUs are capped at 850/1,000 sq ft (1,200 only where ≤10% of lot area), base height is 16 ft with a design-review ladder to 21–24 ft, and the rear setback steps from 4 ft to 8 ft once an ADU exceeds 16 ft. The decisive local wrinkle is the Coastal Zone: most parcels are inside it, so the Local Coastal Program applies on top of state ADU law and parking can be required there. Verify Coastal Zone status, the applicable size tier, and any historic/fire overlay with Santa Cruz Planning.
Frequently asked questions
Can I build an ADU in Santa Cruz?
Yes. California's statewide ADU law requires Santa Cruz to approve a qualifying accessory dwelling unit ministerial (by right), plus a junior ADU (JADU) on a single-family lot.
How big can an ADU be in Santa Cruz?
A detached ADU of at least 1,000 sq ft must be allowed, and an ADU of 800 sq ft can never be zoned out by floor-area or lot-coverage limits. A JADU can be up to 500 sq ft.
What are the setback requirements for an ADU in Santa Cruz?
Side and rear setbacks are limited to 4 ft. No front setback may block the mandatory 800 sq ft / 16-ft / 4-ft-setback ADU; otherwise per base zone.
Is parking required for an ADU in Santa Cruz?
Up to 1 space. No parking can be required within ½ mile of transit, for conversions, or for units inside the primary home. When a garage is converted, replacement parking is not required.
How long does ADU approval take in Santa Cruz?
A complete application must be acted on within 60 days, with ministerial (by right) — no public hearing or discretionary design review for a qualifying ADU.
Do I have to live on the property to build an ADU in Santa Cruz?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Santa Cruz Mun. Code Ch. 24.16, Part 2 (Accessory Dwelling Units)
- Cal. Gov. Code §§ 66310–66342 (ADU Law)
- HCD 2025 Accessory Dwelling Unit Handbook
- Cal. Gov. Code § 66317 (ministerial approval, 60-day deadline)
- Cal. Gov. Code § 66323 (by-right ADU/JADU, 800 sq ft, 4-ft setbacks)
- Cal. Gov. Code § 66333 (junior ADUs)
- Cal. Gov. Code § 66321 (size minimums & height)
- Cal. Gov. Code § 66322 (ADU parking; § 66334 covers JADU parking)
- Cal. Gov. Code § 66314 (local ordinance standards)
- Cal. Gov. Code § 66315 (owner-occupancy)
- Cal. Gov. Code § 66311.5 (impact fees: none for an ADU ≤ 750 sq ft or JADU ≤ 500 sq ft)
Last updated 2026-06-28. This is an AI-assisted summary of Santa Cruz's ADU rules, drawn from its published ordinance and California ADU law — general information, not legal advice, and it may be incomplete or out of date. Verify the controlling rule for your specific parcel with Santa Cruz Planning before relying on it.
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