Santa Cruz County

ADU Pass helps homeowners in Santa Cruz County, California navigate the permit paperwork for building an accessory dwelling unit. We cover 13 cities and 19 ZIP codes in this county.

19 ZIP codes

13 Cities

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County ADU details

County ADU ordinance

Santa Cruz County is a Central Coast California county (population ~262,000) on Monterey Bay's northern shore, with four incorporated cities (Santa Cruz, Watsonville, Capitola, Scotts Valley) and substantial unincorporated territory including Aptos, Soquel, Live Oak, Felton, Ben Lomond, Boulder Creek, Brookdale, Davenport, La Selva Beach, Rio del Mar, Pajaro Dunes, Bonny Doon, and Corralitos. The county is unusual in California ADU history: the unincorporated 1981 Santa Cruz County ADU ordinance was one of the earliest in the state and the city of Santa Cruz pioneered the modern American ADU policy framework with its 2003 program (frequently cited as the model that influenced AB 68 and the broader 2019-2024 statewide preemption regime). The county Board of Supervisors administers ADUs in unincorporated areas under California Government Code Sec. 65852.2 and 65852.22, and the county's ordinance is generally regarded as among the more permissive in California - reflecting the historical policy stance and the acute affordability crisis driven by UCSC's enrollment growth and Silicon Valley commute pressure across Highway 17. The geography is dominated by the Santa Cruz Mountains (which separate the county from Silicon Valley), the Monterey Bay coastline, and the Pajaro Valley agricultural floor in the south. The 2020 CZU August Lightning Complex Fire destroyed approximately 925 homes in the unincorporated county (Bonny Doon, Boulder Creek, Brookdale, Last Chance, Swanton, Davenport hinterland), and post-CZU rebuild streamlining is a major ongoing policy thread - the county adopted expedited rebuild pathways and mass-casualty WUI rebuild programs that intersect with ADU permitting on burn-impacted parcels.

Code citations:

State-floor overlay: California state ADU preemption applies in full to unincorporated Santa Cruz County. Coastal-zone parcels also require Coastal Development Permits (CDPs) under the certified LCP, with Coastal Commission appeal jurisdiction on parcels in the coastal-appeal area. AB 1033 condo-conversion election status: not adopted at the county level as of 2026-04 (city of Santa Cruz under separate review). AB 976 prohibits owner-occupancy mandates on detached ADUs. AB 2533 unpermitted-ADU amnesty applies countywide. SB 9 urban lot-split provisions apply only within incorporated cities, not unincorporated parcels. HCD oversight applies to ordinance amendments per Sec. 65852.2(h); the county's historical stance is generally compliant with state law and frequently more permissive.

Adopting body: Santa Cruz County Board of Supervisors

County permitting (unincorporated parcels)

Santa Cruz County Planning Department / Community Development and Infrastructure (CDI) issues ADU permits for unincorporated parcels including Aptos, Soquel, Live Oak, Felton, Ben Lomond, Boulder Creek, Brookdale, Davenport, La Selva Beach, Rio del Mar, Pajaro Dunes, Bonny Doon, and Corralitos. Practical permitting frictions: California Coastal Zone covers the entire county shoreline and triggers CDP review with Coastal Commission appeal rights; CAL FIRE State Responsibility Area covers most of the Santa Cruz Mountains and back-country with extensive Very High FHSZ - the 2020 CZU August Lightning Complex Fire (~86,500 acres in Santa Cruz and San Mateo Counties combined; ~925 homes destroyed in Santa Cruz County) reset rebuild and WUI rules; FEMA SFHA along the San Lorenzo River, Soquel Creek, Aptos Creek, Pajaro River, and coastal terrace bluffs; tsunami inundation along the Monterey Bay coast (the 2011 Tohoku tsunami caused several million dollars of damage in Santa Cruz Harbor); the Sandhills habitat conservation overlay in the Bonny Doon / Felton / Ben Lomond Mountain area protecting endemic species; Williamson Act ag-preserve parcels in the Pajaro Valley; coastal-bluff erosion setbacks; and well-water / septic considerations on rural parcels not served by the San Lorenzo Valley Water District, Soquel Creek Water District, Central Water District, or Pajaro Valley Water Management Agency.

DepartmentSanta Cruz County Community Development and Infrastructure (CDI), Planning Department

Address701 Ocean Street, Room 400, Santa Cruz, CA 95060

Phone831-454-2580

Process overview: Standard ministerial 60-day review per Sec. 65852.2(b) for compliant ADU applications outside the coastal zone and outside Very High FHSZ. Coastal-zone parcels require concurrent Coastal Development Permit (CDP) issuance through the certified LCP; CDPs are discretionary for parcels in the appealable area, materially extending timelines (3-9 months typical including any appeals). Within Very High FHSZ (most of the Santa Cruz Mountains back-country and CZU burn footprint), Chapter 7A ignition-resistant construction, PRC 4291 defensible space, and CAL FIRE driveway/turnaround review apply. Rebuild Santa Cruz County program offers expedited pathways for replacement structures on CZU-impacted parcels including ADU additions during rebuild. Sandhills habitat parcels (Bonny Doon, Felton, Ben Lomond Mountain) require habitat-impact review for endemic species (Mt. Hermon June beetle, Zayante band-winged grasshopper, Ben Lomond spineflower). Septic-suitability evaluation by Environmental Health is required where no public sewer (most of the San Lorenzo Valley, Bonny Doon, Corralitos, and rural Pajaro Valley).

Impact fees: SB 13 fee waivers apply to ADUs under 750 sqft (no impact fees). Coastal Development Permit fees stack on coastal-zone applications. CAL FIRE driveway/defensible-space inspection fees apply on most Santa Cruz Mountains parcels. Septic permits required on rural parcels. Pajaro Valley Water Management Agency groundwater-augmentation charges apply on Pajaro Valley basin parcels. School-district fees per Education Code Sec. 17620 on ADUs over 500 sqft (Santa Cruz City Schools, Pajaro Valley USD, Soquel ESD, Live Oak ESD, San Lorenzo Valley USD, Scotts Valley USD by sub-area).

County assessor

The Santa Cruz County Assessor maintains parcel-level assessment records for the entire county. ADU additions on unincorporated parcels are captured as improvements via shared permit data with the Planning and Building Departments. California Proposition 13 caps base-year valuation increases at 2 percent per year on the existing structure; new improvement value (the ADU) is added as a separate line item assessed at fair market value at completion. Williamson Act parcels (primarily in the Pajaro Valley agricultural floor) carry agricultural use-value assessment under Sec. 423 of the Revenue and Taxation Code. CZU Fire-impacted parcels qualified for Prop 50 / Prop 171 disaster-relief base-year-value transfer (rebuild within 5 years preserves base-year value for the replacement structure of comparable utility) and Cal. Rev. & Tax. Code Sec. 170 calamity reassessment downward to reflect fire damage; reassessment-on-completion for the rebuilt structure is governed by the comparable-utility rule.

NameSanta Cruz County Assessor

Address701 Ocean Street, Room 130, Santa Cruz, CA 95060

Phone831-454-2002

Assessment policy: ADU improvement value is added on the next regular revaluation cycle following completion. Per Prop 13, the ADU's value is taxed at 1 percent of fair market value at completion (plus voter-approved local rates), while the existing structure remains at its base-year value plus the 2 percent annual cap. Conversion ADUs (within existing structure) typically generate smaller incremental assessments than detached new construction. CZU Fire-impacted rebuilds: replacement structure of comparable utility carries the pre-fire base-year value; an ADU added during rebuild that exceeds comparable-utility floor area is assessed at fair-market new-construction value for the excess.

County overlays (9)

Santa Cruz County overlays of consequence: California Coastal Zone covering the entire county shoreline with certified LCP and Coastal Commission appeal rights on parcels in the appealable area; CAL FIRE State Responsibility Area Very High FHSZ across most of the Santa Cruz Mountains back-country (Bonny Doon, Boulder Creek, Brookdale, Felton, Ben Lomond, Empire Grade, Last Chance, Swanton); 2020 CZU August Lightning Complex Fire burn footprint (~86,500 acres burned, ~925 homes destroyed in Santa Cruz County) with active rebuild streamlining; Big Basin Redwoods State Park (the original 1902 California state park, ~18,000 acres - the CZU Fire severely damaged park infrastructure including the historic park headquarters, which has been progressively reopening 2022-2026); Henry Cowell Redwoods State Park, Forest of Nisene Marks State Park, Wilder Ranch State Park, Castle Rock State Park, the Land Trust of Santa Cruz County easements, and Soquel Demonstration State Forest; UC Santa Cruz campus (the 2,000-acre Upper Campus / Marshall Field / Long Marine Lab footprint plus contiguous undeveloped UC land); FEMA SFHA along the San Lorenzo River, Soquel Creek, Aptos Creek, Pajaro River; tsunami inundation along Monterey Bay; the Sandhills habitat overlay protecting endemic species in Bonny Doon and Ben Lomond Mountain; Williamson Act ag-preserves in the Pajaro Valley; Pajaro Valley Groundwater Sustainability Agency basin (a Sustainable Groundwater Management Act / SGMA basin in critical overdraft); Amah Mutsun Tribal Band tribal-consultation overlay (AB 52 / SB 18) in the historic Mutsun-Awaswas Ohlone territory across the entire county.

Known county issues (4)

policy-review — Coastal-zone CDP friction: the entire county shoreline is in the California Coastal Zone, and parcels in the coastal-appeal area carry Coastal Commission appeal rights that can extend ADU permit timelines from 60 days (state ministerial baseline) to 3-9 months. Owners on the coastal terrace should validate whether the parcel is in the appealable area before assuming a ministerial timeline.
other — CZU Fire rebuild constraints: ~925 homes destroyed in 2020 CZU August Lightning Complex Fire; many rebuilds remain in progress as of 2026-04. Insurance availability is acutely constrained in the Santa Cruz Mountains FHSZ, particularly Bonny Doon, Boulder Creek, and Brookdale. ADU additions during rebuild require coordination of comparable-utility base-year-value rules, FHSZ Chapter 7A construction, septic, and Sandhills habitat review.
other — Sandhills habitat: Bonny Doon, Felton, and Ben Lomond Mountain Sandhills parcels host federal- and state-listed endemic species. ADU permits trigger habitat-impact review and can require mitigation credits or on-site conservation easements.
policy-review — UCSC enrollment-driven demand: UC Santa Cruz enrollment growth is the dominant medium-term housing-demand driver in the county. ADU production in the city of Santa Cruz and contiguous unincorporated areas (Live Oak, Soquel, Felton) is closely tied to student-housing pressure across Highway 17 from Silicon Valley.

California state — ADU law and programs

State ADU law

California has the most aggressive statewide ADU preemption regime in the US, built from ~15 bills passed 2019-2025 and enforced by the Department of Housing and Community Development (HCD). The 2026 HCD ADU Handbook addendum (in effect with the 2025 Title 24 code cycle) is the operative state-level reference. The regime does four things at once: (1) preempts local zoning that would ban or unreasonably restrict ADUs; (2) imposes by-right ministerial approval with short statutory deadlines; (3) caps fees and utility-connection charges; and (4) empowers HCD to void non-compliant local ordinances.

State HOA preemption

California has the strongest statewide HOA-preemption regime in the US for accessory dwelling units, built from two bills: AB 670 (2019) voided ADU-prohibiting covenants on single-family residential lots, and AB 3182 (2020) extended and codified the preemption into the Davis-Stirling Common Interest Development Act (Civil Code §§ 4740 / 4741). The combination prohibits common-interest communities from banning ADUs, restricting rentals below 25% of separate interests, or treating ADUs as separate HOA interests. Limits remain: HOAs retain authority over reasonable design standards and statutory height limits, and the 2026 Carlsbad case (CalMatters coverage) established that an HOA's documented design-standards regime can effectively delay or constrain ADU approval short of outright prohibition.

State financing programs

California's flagship state-level ADU financing program — the CalHFA ADU Grant Program — is paused and has not been refunded since the original $100 million allocation was fully deployed 2023-12-28. The program provided up to $40,000 per qualifying homeowner for pre-construction and non-recurring closing costs and financed approximately 2,500 ADUs in two rounds. As of 2026-04, no new funding round has been announced in the state budget. CalHFA continues to publish anti-scam warnings because bad actors actively solicit homeowners claiming access to grant funds that no longer exist. State-level financing activity has shifted to local pilot programs (San Francisco, San Jose, Los Angeles, San Diego) and private financing products (Fannie Mae ADU mortgage, HELOC, construction-to-permanent).

CalHFA ADU Grant Program
HCD ADU Funding index

State housing programs

California's state-level ADU programs are concentrated at HCD (technical guidance, ordinance review, enforcement) and the paused CalHFA grant pipeline (covered under stateFinancing). The state does not operate a central pre-approved ADU plan library — instead, AB 1332 (2024) created a preemption framework for local pre-approved plans with a 30-day ministerial-approval deadline, and major cities (Los Angeles, San Diego, San Jose, Sacramento, Berkeley) have rolled out their own plan catalogs. The California YIMBY coalition and other housing-policy organizations play an influential role in bill drafting; they are not state agencies but effectively drive much of the ADU legislative agenda. The Title 24 code cycle (now 2025, in effect for 2026 permits) is the authoritative building-code baseline.

Federal (United States) — ADU-relevant rules and programs

Federal ADU law

The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.

Federal financing programs

Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.

Federal tax credits

There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.

Federal housing programs

HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.