Santa Clarita ADU connects Santa Clarita Valley homeowners with a local ADU contractor. We don’t build ADUs ourselves. You call or send us your details, and we pass them to a contractor who follows up with you directly. Most ADU projects here cost about $100,000 to $350,000 or more, depending on type, size, and site.
Call (661) 486-8393 or send us your details to get started.
How does getting matched with an ADU contractor work?
It’s simple. There are four steps:
- Call or send your details. 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 pass your details to a local ADU contractor. Your information goes to a contractor who builds ADUs in the Santa Clarita Valley.
- The contractor contacts you. They follow up directly to talk through your project.
- You decide. There’s no obligation to hire. Before you sign anything, check the contractor’s license using the steps below.
What type of contractor builds an ADU in California?
Most ADUs are built by a general contractor with a California Class B (General Building) license from the Contractors State License Board (CSLB). That contractor manages the build and hires the trades. Several other roles are usually involved:
| Role | What they do | When you need them |
|---|---|---|
| General contractor (Class B) | Runs the build, hires subcontractors, usually pulls permits | Every site-built ADU |
| Designer or architect | Draws plans that meet city or county standards | Most projects, unless you use a design-build firm or prefab plan |
| Structural engineer | Calculates foundations, framing, and loads | Detached units, sloped lots, raised garage roofs |
| Title 24 energy consultant | Prepares the energy compliance report | New living space, including most conversions |
| Design-build firm | Handles design and construction under one contract | When you want a single point of contact |
| Prefab or modular maker | Builds the unit in a factory; a local contractor does site work | When speed matters more than customization |
Which contractor fits your ADU type?
Match the contractor to the kind of ADU you’re building. A great garage-conversion crew may have never poured a foundation for a detached unit.
| ADU type | Typical cost in Santa Clarita | Look for a contractor who has done |
|---|---|---|
| Garage conversion | About $100,000 to $220,000 | Egress windows, insulation, utility upgrades, raised rooflines |
| Junior ADU (up to 500 sq ft, inside the home) | About $50,000 to $120,000 | Interior remodels with a separate entrance and efficiency kitchen |
| Attached ADU | About $200,000 to $350,000 | Home additions tied into an existing roof and foundation |
| Detached ADU | About $150,000 to $350,000+ | New foundations, full framing, separate utility runs |
| Prefab or modular ADU | Varies by manufacturer | Site prep, crane placement, and utility hookups |
See the ADU cost breakdown for what drives each number.
How much do ADU contractors in Santa Clarita charge?
Most ADU projects in the Santa Clarita Valley cost about $100,000 to $350,000 or more in 2026. Contractors price by the project, not by the hour. These factors move the price most:
- ADU type and size. Conversions reuse existing structure. Detached units need everything new.
- Site conditions. Slopes and long utility runs add grading and trenching costs.
- Sewer or septic. Septic properties may need an evaluation or upgrade before approval.
- Fire hazard zones. Very High Fire Hazard Severity Zones add access and fuel modification requirements.
- HOA rules. Architectural review can require specific materials or colors.
- Finish level. Cabinets, flooring, and fixtures swing costs by tens of thousands.
California law protects you on payments. On a home improvement contract, the down payment can’t exceed $1,000 or 10 percent of the contract price, whichever is less. The exception is a contractor with a blanket performance and payment bond on file with CSLB. After that, each progress payment should match work and materials already delivered.
Every property is different, so treat any number as a range until a contractor visits your site. See ADU financing options if you’re planning how to pay for it.
Does it matter whether you’re in the city or LA County?
Yes. Four communities are inside City of Santa Clarita limits. Four are unincorporated LA County, with a different permitting office and ordinance. A contractor who knows your agency avoids delays.
| Community | Where permits go | Common site factors |
|---|---|---|
| Valencia | City of Santa Clarita | HOA architectural review in most tracts |
| Newhall | City of Santa Clarita | Older lots; Old Town Newhall often has no HOA |
| Saugus | City of Santa Clarita | Older Bouquet Canyon lots and newer HOA tracts |
| Canyon Country | City of Santa Clarita | Some Sand Canyon parcels in fire hazard zones |
| Stevenson Ranch | LA County | HOA review is common |
| Castaic | LA County | Some outlying parcels on septic or in fire zones |
| Acton | LA County | Septic systems and fire hazard zones are common |
| Agua Dulce | LA County | Septic systems and fire hazard zones are common |
Both agencies follow the same state rules. A compliant ADU gets ministerial review with no public hearing, and state law requires a decision within 60 days of a complete application.
What should you ask an ADU contractor before hiring?
Ask these eight questions of every contractor you consider. Get the answers in writing.
- What is your CSLB license number and classification?
- How many ADUs have you completed in the Santa Clarita Valley?
- Have you permitted projects with my agency, the city or LA County?
- Who draws the plans, and who pulls the permits?
- Do you carry workers’ compensation and general liability insurance?
- What does the bid exclude, such as trenching, septic work, or fire sprinklers?
- What is the payment schedule, and which milestone triggers each payment?
- What warranty do you give on labor and materials?
What are the red flags when hiring an ADU contractor?
Walk away if a contractor does any of these:
- Asks for more than $1,000 up front without a blanket bond on file
- Leaves the license number off the bid or contract
- Suggests skipping permits to save money
- Wants cash only or pushes you to sign today
- Gives a one-line lump-sum bid with no scope details
- Asks for payments ahead of completed work
You can check any license for free with CSLB’s online license check. It shows status, classification, bond, and workers’ compensation coverage.
When is a traditional contractor not the best fit?
A custom site-built ADU isn’t right for everyone. A prefab or modular unit may suit you better if you want a standard floor plan and a shorter build. Homeowners can also act as their own owner-builder, but that means taking on the permits, inspections, and liability yourself.
Ready to find an ADU contractor?
Call (661) 486-8393 or send us your project details. Leave your name, phone number, address, and the type of ADU you want, and we’ll pass your details to a local contractor.
ADU contractor FAQs
Does Santa Clarita ADU build ADUs?
No. Santa Clarita ADU is a referral service, not a contractor. When you call or send your details, we pass them to a local ADU contractor who follows up with you. You sign your construction contract directly with the contractor you choose.
Do I need a licensed contractor to build an ADU in California?
Not legally, but most homeowners use one. California allows owner-builders to pull their own permits. In that case, you take responsibility for code compliance, inspections, and any workers you hire. A Class B general contractor takes that on for you.
Who pulls the permits for an ADU, me or the contractor?
Usually the contractor. CSLB notes that contractors generally pull permits, but your contract should say who is responsible for permits and their fees. Confirm this before you sign.
How long does it take to build an ADU in Santa Clarita?
Most ADU projects take 6 to 12 months from design to completion. Garage conversions often take 2 to 4 months of construction. Detached units commonly take 4 to 8 months to build, plus roughly 4 to 6 weeks for permits.
Can one company design and build my ADU?
Yes. Design-build firms handle plans and construction under one contract. That gives you a single point of contact. Separate designers and contractors can give you more design freedom and more bids to compare.
How do I check an ADU contractor’s license?
Use the free license check on the CSLB website. Search by name or license number. It shows whether the license is active, its classification, the bond, workers’ compensation status, and any disciplinary actions.