Find out what your backyard
could realistically become
Get a preliminary look at potential ADU options, likely cost ranges, and the property considerations that matter — then meet up to three carefully selected local builders when you're ready. No pressure, no obligation.
Find the right ADU
for your property and goals
Not all ADUs are created equal — the right choice depends on your lot, your budget, and what you're trying to accomplish.
Cost, rent and value-added ranges above are general market estimates for planning purposes only — not quotes, appraisals or guarantees. Actual numbers depend on your property, market conditions and financing; a licensed contractor, appraiser or lender can give you figures specific to your project. Not sure which type fits? Take our 60-second ADU quiz, see our garage conversion vs. detached and JADU vs. full ADU comparisons, or check our size & setback calculator to see the minimum your city must allow.
More than extra space —
a real financial opportunity
Here's why homeowners across Southern California are building ADUs right now.
These are general patterns, not guarantees — actual value, financing terms and rental income depend on your property, market conditions, and lender requirements. See our guides on whether an ADU increases property value and ADU rental income for more detail.
Not every contractor makes it into our network
We focus on contractors who meet clear standards for licensing, insurance, relevant project experience, communication, and professional estimating — not just anyone with a license and a truck. Before we introduce a contractor, they're reviewed against the same four standards.
We'd rather introduce you to a short list of contractors who meet those standards than a long directory of anyone with a license. That bar applies to every introduction we make.
No retainers. No hidden fees. No going quiet after the intro.
We built United Build Partners to be the advisor homeowners wish they'd had from day one. Tap each item to see exactly how that works in practice.
United Build Partners doesn't stop at a contractor introduction. We help bring together everyone your project needs — contractors, architects and permit specialists. Experienced professionals can help reduce preventable delays through complete submissions, local familiarity, and coordinated scheduling — from plan review through utility hookups. See our guide on comparing multiple contractor bids once you're matched, our contractor red flags checklist before you sign anything, and our contractor warranty guide to know what coverage to expect once construction is done.
State law generally requires cities to act on a complete ADU permit application within 60 days — one reason ADU projects often move through permitting faster than a typical home addition. Timelines still vary by city and project — see our full construction timeline guide for a phase-by-phase breakdown.
Some contractors in our network offer pre-approved ADU plan sets. Building from an already-approved design may reduce portions of the design and plan-review process — a real time saver, though site-specific approvals, permits, utilities, and site conditions still apply.
Homeowners do not pay United Build Partners directly for the initial property assessment or contractor introductions. United Build Partners may receive compensation from participating contractors.
Here's exactly what happens next
No guesswork — this is the real process, start to finish.
What United Build Partners does
— and what we don't
We're a homeowner-focused ADU advisory and contractor-introduction service. We are not the construction company.
Those decisions and agreements are always between you and your licensed contractor.
What ADUs generally cost
Construction costs in our service area generally run $285–$350 per square foot, though the exact rate varies by finish level, site conditions, and contractor. These are planning estimates only — your actual cost depends on your property, design choices, and local permitting requirements.
| ADU Type | Low End | High End | Typical Build Time |
|---|---|---|---|
| Junior ADU (JADU) | $70,000 | $140,000 | 2–5 mo |
| Garage Conversion | $115,000 | $210,000 | 4–8 mo |
| Attached ADU | $140,000 | $280,000 | 6–11 mo |
| Prefab / Modular | $140,000 | $350,000 | 3–6 mo |
| Detached ADU | $170,000 | $420,000+ | 8–15 mo |
The table above is illustrative of hard construction costs only, based on general Southern California market ranges. Total project cost typically also includes design and engineering, permit and impact fees, utility connections, and site work — all of which vary by city and property. These are not quotes, bids, or guarantees. A licensed contractor can give you a firm, written estimate for your specific project. Financing it? Our loan payment calculator estimates a monthly payment from your own loan amount, rate and term.
Assumes hard construction of $285–$350 per square foot, adjusted by ADU type, with design, permits and contingency added as typical planning allowances. Site work and utility connections vary by property and can add more. This is a rough, illustrative planning range only — not a bid, appraisal, or financial guarantee. Confirm actual costs with licensed professionals.
Get a Real EstimateRun your own numbers
before anyone calls you
Every tool is free, works right in your browser, and stores nothing. They're built from the same statutory rules and published ranges we use in real property reviews — so what you see here is what we'd tell you.
See all 10+ free tools → · Vetting a builder? Run their bid past our contractor red-flags checklist before you sign anything.
Now serving four Southern California counties
United Build Partners is currently accepting property-review requests across select communities in Los Angeles, Orange, San Bernardino, and Riverside counties. Contractor availability varies by project type, location and timing.
Coming soon: San Diego County. We're preparing to expand service there next. If you're a San Diego County homeowner, feel free to reach out now and we'll follow up as soon as we're accepting requests in your area.
United Build Partners is a homeowner-focused ADU advisory and contractor-introduction service. We help you understand your property's ADU options and, when appropriate, introduce you to up to three licensed contractors who may be suited to your project.
No. Your request is reviewed first — by a person — and if your project is a fit, it's shared with at most three licensed contractors matched to it. It's never posted to a directory or blasted out to a list. If an ADU isn't realistic for your lot, we'll tell you that directly instead of passing your information along anyway. And you can ask us at any time to stop contacting you or to delete your information — see our Privacy Policy.
Property-review requests go to a dedicated United Build Partners advisor directly — not to a call center or a queue. You work with the same advisor from your first inquiry through contractor introductions, and you can reach us any time at 714-705-6901 or contact@unitedbuildpartners.com.
Construction costs in our service area generally run $285–$350 per square foot, though your exact cost depends on ADU type, finish level, site conditions, and the contractor you choose. Our Cost Education section breaks down typical ranges by ADU type, our full cost guide covers what drives the price, and our calculator can give you a rough estimate based on your square footage.
Homeowners generally build an ADU for some mix of three reasons: added property value, long-term rental income, and the ability to refinance and access cash once it's complete. In many Southern California markets, a well-built ADU can add more resale value than it costs to build. Actual returns depend on your property, market and financing — see "The ADU Opportunity" section above, and talk to a real estate professional and lender for numbers specific to your situation.
We're currently accepting property-review requests across select communities in Los Angeles, Orange, San Bernardino and Riverside counties. San Diego County is coming soon. Contractor availability varies by location, project type and timing.
Up to three. We don't guarantee three contractors will be available for every project — it depends on your location, project type, and timing.
We review your project details and may contact you to clarify your property, goals, timing and budget. If it looks like a good fit, your information may be shared with up to three matched contractors, who may contact you directly. See the "What Happens Next" section above for the full walkthrough.
Start by submitting your property details — we'll take a first look based on your lot and location. From there, your local building department and a licensed contractor will confirm exactly what's allowed on your specific parcel. Our guides on who can build an ADU in California and finding your property's zoning cover the basics. We don't guarantee eligibility, permits, or approval, since that's ultimately determined by your city, not by us.
No. United Build Partners is not a general contractor, architect, engineer, lender, or real estate broker, and we're not a government agency. We're an advisory and introduction service — the licensed contractor you choose performs the actual design and construction work. See our architect vs. design-build guide for how that team is typically structured.
You're never obligated to move forward with any contractor we introduce, and there's no cost to you for the initial property review. Homeowners don't pay United Build Partners directly — we're compensated by participating contractors for the introductions and site visits we arrange, and when a project moves forward.
California law generally requires cities to act on a complete ADU permit application within 60 days, which is one reason ADU projects often move faster than a typical remodel or addition. Some contractors in our network also offer pre-permitted plan sets, which can shorten the design and permitting phase even further. Actual timelines still depend on your city and project specifics — see our California ADU laws guide for the full picture.
Curious what your property could support?
Share a few details about your property and goals. We'll help you understand your options and, when appropriate, introduce you to up to three licensed contractors.