Santa Clarita ADU Size Limits, Setbacks, Height & Parking (2026)

In the City of Santa Clarita, a Junior ADU can be up to 500 sq ft, and the city’s 2026 ADU handout lists 800 sq ft for a detached ADU. State law caps side and rear setbacks at 4 feet, allows most detached ADUs to be 16 feet tall, and bars lot coverage rules from blocking an ADU of at least 800 sq ft. The city’s handout says there are no parking requirements for ADUs or JADUs.

The city updated its ADU rules in April 2026, so confirm current limits for your design with the Planning Division at (661) 255-4330. Lots in unincorporated areas follow LA County’s rules, which also must meet state law.

How big can an ADU be in Santa Clarita?

ADU type	Size
Junior ADU	Up to 500 sq ft, within the walls of the home
Detached ADU	800 sq ft listed in the city’s 2026 handout
Converted ADU	Created within existing space; the handout lists no maximum
State floor for any local maximum	A city can’t set its maximum below 850 sq ft for a studio or 1-bedroom, or 1,000 sq ft for 2+ bedrooms

Because the handout’s detached figure and the state floor differ, ask the Planning Division which size path fits your design before you draw plans. Square footage is measured as interior livable space under SB 543.

What are the setback rules?

Side and rear: no more than 4 feet for a new ADU.
Conversions: no setback is required for an ADU created from an existing structure, though fire and safety rules apply.
Front: generally follows your zone, but front setbacks can’t be used to block an 800 sq ft ADU with 4-foot side and rear setbacks.

A quick way to see your space: lot width minus 8 feet gives the width available in the backyard. Then measure from the back of your house, plus any required separation, to 4 feet from the rear lot line.

How tall can an ADU be?

ADU	Height state law allows
Detached, most lots	16 feet
Detached, within a half mile of major transit	18 feet, plus 2 feet for roof pitch
Detached, on a lot with a multistory multifamily building	18 feet
Attached to the main house	25 feet or the zone’s height limit, whichever is lower

The city’s handout lists 16 feet for a detached ADU and 18 feet to the top plate within a half mile of transit. An attached ADU can’t be required to exceed two stories, so a two-story attached ADU may be possible where zoning allows. Most detached ADUs are single story.

Do you need parking for an ADU?

In the City of Santa Clarita, no. The city’s 2026 handout says there are no parking requirements for ADUs or JADUs.

In unincorporated LA County areas, state law still bars parking requirements in many cases, including when:

The ADU is within a half mile walking distance of public transit
It’s in a historic district
It’s part of the main house or an existing accessory structure
On-street parking permits are required but not offered to the ADU occupant
A car-share vehicle is within one block

When a garage is converted to an ADU, the lost parking doesn’t have to be replaced.

Can lot coverage stop an ADU?

Not one of at least 800 sq ft. State law says lot coverage, floor area ratio, open space, front setbacks, and minimum lot size can’t be used to deny an ADU of at least 800 sq ft with 4-foot side and rear setbacks that meets other local standards, such as height.

What can the city still regulate?

Objective design standards
Height within state minimums
Building, fire, and energy codes
Oak tree protection and fire hazard requirements
Utility connections

Want someone to check what fits on your lot?

Call (661) 486-8393. If no one answers, leave a voicemail with your name, phone number, address, and the type of ADU you want. You can also use the contact form. We’ll pass your details to a local ADU contractor, who will follow up with you directly. There’s no obligation to hire.

ADU size and setback FAQs

What is the maximum ADU size in Santa Clarita?

The city’s 2026 handout lists 800 sq ft for a detached ADU and 500 sq ft for a JADU. State law says a city’s maximum can’t be below 850 sq ft for a 1-bedroom or 1,000 sq ft for 2+ bedrooms, so confirm with the Planning Division which applies to your design.

What are the ADU setback requirements in California?

No more than 4 feet from side and rear lot lines for a new ADU, and none for an ADU converted from an existing structure.

Can I build a two-story ADU?

An attached ADU can be up to 25 feet or the zone’s height limit, whichever is lower, which may allow two stories. Most detached ADUs are limited to 16 feet, which fits a single story.

Does an ADU need parking in Santa Clarita?

No. The City of Santa Clarita’s handout says there are no parking requirements for ADUs or JADUs.

Is there a minimum lot size for an ADU?

No. State law doesn’t allow a minimum lot size requirement for ADUs.

Santa Clarita ADU Size, Setback, Height, and Parking Rules (2026)