Everything homeowners need to know about building an accessory dwelling unit in Santa Clarita - size limits, setbacks, permits, and a local ordinance that was just overhauled to catch up with California's statewide ADU law.
Last verified: August 2026
8/10 · ADU-friendly
1,200 sq ft*
Max ADU size
16 ft*
Max height
Not required
Owner-occupancy
By-right
Permit type
This page summarizes Santa Clarita Municipal Code Section 17.57.040 (Unified Development Code) and California's statewide ADU law (Government Code Section 65852.2 and related sections) for general reference - it is not legal advice. The city adopted significant amendments to this section in spring 2026 (see ordinance history below). Always confirm current requirements with the Santa Clarita Planning Division before designing or applying for permits. See sources below.
Zoning & size requirements
What you're allowed to build
ADU type
Max size
Max height
Notes
Detached (new construction)
1,200 sq ft
16 ft under the base local standard, with additional height allowed in some circumstances under state law
4 ft side/rear setbacks; oak trees and High Fire Hazard Severity Zone status can no longer be used to deny an ADU, as of the city's 2026 ordinance update
Attached (addition, above-garage)
850 sq ft (studio/1-bedroom) or 1,000 sq ft (2+ bedrooms)
Matches the primary structure; two-story configurations above an existing garage are permitted under state law in some cases
Common approach for above-garage conversions
Conversion ADU + new detached ADU (combined)
A converted ADU within the existing home's footprint, plus a new detached ADU of up to 800 sq ft on the same lot
800 sq ft detached unit: 4 ft side/rear setbacks
State law allows this "conversion plus new build" combination on a single-family lot, on top of a JADU
Junior ADU (JADU)
500 sq ft, attached
Within existing primary structure
Must be built within the walls of the existing home
Allowed zoning districts
Residentially zoned parcels citywide under SCMC Section 17.57.040. Santa Clarita is a newer, largely master-planned city with numerous HOA-governed communities; the city's zoning code doesn't let an HOA block a code-compliant ADU, but private CC&Rs may still address exterior design, so check your HOA's governing documents alongside the city's own review.
Additional standards
Setbacks, parking & other rules
Setbacks
4 ft minimum from side and rear property lines for detached ADUs, matching the statewide floor
Parking
1 space required per ADU, waived for garage conversions and for ADUs within a half-mile of a transit stop, along with other state-listed exemptions
Units per lot
Up to 3 additional units on a single-family lot when using the conversion-plus-new-build pathway (1 conversion ADU, 1 new detached ADU up to 800 sq ft, 1 JADU); multifamily lots can add up to 8 detached ADUs under SB 1211
Owner-occupancy
Not required for ADUs, permanently eliminated statewide by AB 976 effective January 1, 2024
Oak trees & fire zones
As of the city's spring 2026 ordinance update, oak tree protections and High Fire Hazard Severity Zone status can no longer be used as grounds to deny an ADU; building and fire code requirements (defensible space, ignition-resistant construction) still apply to construction itself
Rental rules
A 30-day minimum rental term applies; short-term rentals of an ADU or JADU are prohibited
Ordinance history
How Santa Clarita's ADU rules got here
2017Statewide by-right ADU law takes effect. California Government Code Section 65852.2 begins requiring cities, including Santa Clarita, to approve most ADUs ministerially.
2023State flags Santa Clarita's ordinance. An HCD review dated March 24, 2023 identified provisions in the city's ADU standards that didn't align with state law, including restrictions tied to oak trees and High Fire Hazard Severity Zones.
2024Owner-occupancy ban made permanent. AB 976, effective January 1, 2024, permanently prohibits California cities from requiring owner-occupancy for ADUs.
2026Council overhauls the local ordinance. Facing continued state pressure and the threat of litigation from housing-advocacy groups, the City Council passed amendments to SCMC 17.57.040 on first reading April 14, 2026 (4-1, Councilmember McLean dissenting) and gave final approval on second reading April 28, 2026. The city's attorney told the Council that HCD had rejected the local fire-zone and oak-tree restrictions outright, noting similar denials for Los Angeles County and Berkeley. The update removed those restrictions, added the 60-day approval "shot clock," and codified the conversion-plus-new-build unit combination for single-family lots.
Worth knowing: the April 2026 vote wasn't unanimous. Mayor Pro Tem Patsy Ayala called the changes "Sacramento-driven compliance" and raised questions about tracking impacts on parks and services, while resident and planning advocate Lynne Plambeck urged the Council to weigh wildfire evacuation risk and oak tree loss before voting. The amendments passed anyway, reflecting how little discretion state law now leaves individual California cities on ADU policy.
Permit process
How Santa Clarita ADU permitting works
1
Pre-application check
Confirm your zoning and any site-specific conditions with the Santa Clarita Planning Division, 23920 Valencia Blvd., Suite 140, (661) 255-4330, before you design.
2
Prepare your plan set
You'll need a site plan, floor plans and elevations, and existing floor plans of the primary home if you're relying on a size formula tied to it.
3
Submit through the Permit Portal
Applications and plan-check tracking go through the city's online Permit Portal at santaclarita.gov.
4
Ministerial plan review
State law requires a decision within 60 days of a complete application; no discretionary hearing is required for a code-compliant design.
5
Building & Safety permits
Building, electrical, plumbing, and mechanical permits are issued through Building & Safety, (661) 255-4935, before construction begins.
6
Inspections
Schedule the standard framing, plumbing, electrical, and final inspections as construction proceeds.
If your property has oak trees or sits in a High Fire Hazard Severity Zone, those factors can no longer be used to deny your ADU under the 2026 ordinance update, though standard building and fire code construction requirements still apply. Fees and timelines are approximate - confirm current figures with the Planning Division.
Budgeting
What it costs to build an ADU in Santa Clarita
Garage conversion
Roughly $70,000-$180,000, the least expensive path since the shell already exists
Basement conversion
Uncommon in Santa Clarita's largely slab-built housing stock; where feasible, costs run comparable to or higher than a garage conversion
New detached ADU
Roughly $150,000-$350,000+ for a code-compliant, freestanding unit
Permit fees
Reported at roughly $10,000-$20,000 total across building, electrical, plumbing, and mechanical permits; design and architectural fees typically add another 10-15% of construction cost
Impact fees
ADUs of 750 sq ft or less are exempt from most local impact fees under state law; the city retains the ability to charge impact fees on larger ADUs
These are general ranges from local contractor estimates and regional reporting, not quotes - actual cost depends heavily on lot conditions, finishes, and whether your site needs oak tree protection measures or fire-hardening details during construction.
Before you apply
Tips for a smooth approval
Check your HOA's governing documents, not just city zoning. Santa Clarita's code can't let an HOA block a compliant ADU outright, but many planned communities still have design review for exterior changes, so plan for both approvals.
Ask about the conversion-plus-new-build combination. If you convert existing space (like a garage) into an ADU, state law lets you also add a new detached ADU up to 800 sq ft on the same single-family lot, on top of a JADU.
Don't assume oak trees or fire-zone status will block your project. The city's 2026 ordinance update removed both as grounds for denial, though defensible-space and ignition-resistant construction requirements still apply on qualifying lots.
Plan your rental strategy around the 30-day minimum. Santa Clarita prohibits short-term rentals of ADUs and JADUs, so this is long-term housing only.
Keep new construction at or under 750 sq ft if avoiding impact fees matters to you. The city retains authority to charge impact fees on larger ADUs.
FAQ
Common questions
Do I need to live on the property to build an ADU in Santa Clarita?
No. California's AB 976 permanently eliminated owner-occupancy requirements for ADUs statewide as of January 1, 2024.
How many ADUs can I build on one lot?
On a single-family lot, state law allows a combination of 1 converted ADU, 1 new detached ADU up to 800 sq ft, and 1 JADU when the conversion pathway is used. Multifamily lots can add up to 8 detached ADUs under SB 1211.
Do I need extra parking for an ADU?
Generally 1 space, but it's waived for garage conversions, ADUs within a half-mile of transit, and other state-listed exemptions.
How long does the permit process take?
State law requires a ministerial decision within 60 days of a complete application, with no discretionary hearing for a code-compliant design. Confirm current timelines with the Planning Division.
What's the maximum size for a detached ADU in Santa Clarita?
1,200 sq ft under the city's standard new-construction pathway, with a 16 ft base height limit. A detached ADU built alongside a converted ADU on the same lot is capped at 800 sq ft under the state-law combination pathway.
How much does an ADU cost to build in Santa Clarita?
Garage conversions tend to run roughly $70,000-$180,000, and new detached units roughly $150,000-$350,000 or more, based on local contractor estimates and regional reporting. Permit fees are reported at roughly $10,000-$20,000 on top of construction cost.
Can oak trees or fire hazard zones stop my ADU project?
No, not as grounds for denial. Santa Clarita's April 2026 ordinance amendment removed both oak tree protections and High Fire Hazard Severity Zone status as reasons to deny an ADU, after the state found those restrictions didn't comply with ADU law. Standard building and fire code construction requirements still apply.
Will my HOA's rules affect my ADU?
The city's zoning code doesn't let an HOA block a code-compliant ADU outright, but many of Santa Clarita's planned communities have their own CC&Rs governing exterior design, materials, and colors. Check your HOA's documents in addition to the city's own review.
