An accessory dwelling unit (ADU) is a second home on the same lot as your house, with its own space to live, sleep, cook, and bathe. In the Santa Clarita Valley you can build one as a detached backyard unit, an attached addition, a garage conversion, or a Junior ADU inside your home. This page covers the rules that decide what you can build, and links to the detailed guides.
What types of ADUs can you build in Santa Clarita?
| Type | What it is | Best for |
|---|---|---|
| Detached ADU | A freestanding unit in the yard | Privacy and rental income on lots with room |
| Attached ADU | An addition that shares a wall with the house | Lots too tight for a separate structure |
| Garage conversion | An existing permitted garage turned into living space | The lowest-cost way to build a full ADU |
| Junior ADU (JADU) | Up to 500 sq ft inside the walls of the house, including an attached garage | Family members or live-in help on a tight budget |
How big can an ADU be in Santa Clarita?
The City of Santa Clarita’s 2026 ADU handout lists these limits for Valencia, Newhall, Saugus, and Canyon Country:
| Type | Size | Setbacks | Height |
|---|---|---|---|
| Detached | 800 sq ft | 4 ft side and rear | 16 ft, or 18 ft to the top plate within a half mile of transit |
| Converted (garage or existing space) | No maximum listed | Fire and safety setbacks | Existing structure |
| Junior ADU | 500 sq ft | Fire and safety setbacks | Within the house |
State law also says a city can’t set its maximum below 850 sq ft for a studio or 1-bedroom ADU, or 1,000 sq ft for 2+ bedrooms, so ask the Planning Division which size path fits your design. See ADU size, setback, height, and parking rules.
How many ADUs can you have on one lot?
On a single-family lot, state law allows a converted ADU, a new detached ADU, and a Junior ADU to be combined, and the City of Santa Clarita’s 2026 handout says you may have each type of ADU on your property. Starting January 1, 2027, AB 956 also allows two detached ADUs, though a city then isn’t required to approve a JADU. See how many ADUs you can build on one lot.
Do you need a parking space for an ADU?
In the City of Santa Clarita, no. The city’s 2026 ADU 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, is part of the main house or an existing accessory structure, or is in a historic district. When a garage is converted to an ADU, the lost parking doesn’t have to be replaced.
Can you rent or sell an ADU?
- Renting: yes, for terms of more than 30 days. The City of Santa Clarita doesn’t allow ADUs to be rented for less than 30 days, and state law sets the same minimum for every JADU and most garage conversions.
- Selling: no. An ADU can’t be sold separately from the main house.
- Living on site: not required for an ADU. For a JADU, the owner must live on the property only if the JADU shares a bathroom with the main house (AB 1154, effective January 1, 2026).
How does ADU permitting work?
A compliant ADU gets ministerial review, with no public hearing, and a decision is due within 60 days of a complete application. In the city, the Planning Division reviews the ADU first, then Building & Safety checks the construction plans. In LA County areas, Regional Planning reviews the site plan, then Public Works Building & Safety reviews the plans. Each community page walks through the steps for that area.
A few local rules add steps. In the city, lots with oak trees need clearance from the Urban Forestry Division, and lots in a high fire hazard severity zone face access requirements. Septic systems, common in rural county areas, bring an Environmental Health review.
How much does an ADU cost?
Most ADUs in the Santa Clarita Valley cost about $100,000 to $350,000 or more in 2026. A Junior ADU can run $50,000 to $120,000 and a garage conversion about $100,000 to $220,000. See the ADU cost breakdown for ranges by type and the fees state law limits, and financing an ADU for ways to pay.
Does an ADU add value to your home?
It usually adds usable space and can add rental income, but the dollar value varies. Appraisers rely on comparable sales, and homes with permitted ADUs are still a small share of sales in most neighborhoods. For an estimate for your address, ask a local real estate agent or appraiser rather than relying on national averages.
Ready to talk to a contractor?
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 basics FAQs
What is the difference between an ADU and a JADU?
A JADU is up to 500 square feet and must be inside the walls of the house, including an attached garage. It needs only an efficiency kitchen and can share a bathroom with the house. An ADU can be detached, attached, or a converted garage, and it has its own full kitchen and bathroom.
Do I need a minimum lot size to build an ADU?
No. California law doesn’t allow cities or counties to require a minimum lot size for an ADU. What matters is whether the unit fits within setbacks and other standards on your lot.
How tall can a detached ADU be in Santa Clarita?
The City of Santa Clarita’s handout lists 16 feet. Within a half-mile of a transit stop, a detached ADU can reach 18 feet plus 2 feet for roof pitch. Attached ADUs can reach 25 feet, up to two stories.
Can my HOA stop me from building an ADU?
No. California law doesn’t allow an HOA to ban ADUs, but it can apply reasonable design rules, such as materials and colors. Expect HOA architectural review in Valencia, Stevenson Ranch, and many newer tracts.
Who do I call to confirm ADU rules for my property?
In the City of Santa Clarita, call the Planning Division at (661) 255-4330 or visit 23920 Valencia Blvd, Suite 140. In unincorporated areas, contact the LA County Department of Regional Planning.
Related ADU guides
- California ADU laws 2026
- Santa Clarita ADU size, setback, height, and parking rules
- How many ADUs can you build on one lot?
- Is my lot eligible for an ADU?
- All Santa Clarita ADU guides
Sources
- City of Santa Clarita Planning Division: ADU handout (2026) (size, setback, height, parking, and rental rules)
- City of Santa Clarita Planning Division: FAQs
- LA County Department of Regional Planning: Accessory Dwelling Units
- California HCD: ADU Handbook (state ADU law)