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Transparent, Fixed-Price ADU Pricing

ADU Cost in Los Angeles, Orange County & San Bernardino

Real ADU cost data, not vague guesses. Building an accessory dwelling unit in Southern California typically costs between $80K and $350K depending on type, size, finishes, and site conditions. Renova Built is a licensed design-build contractor that quotes one fixed price covering design, permits, and construction, so the number you see is the number you pay. Final pricing depends on site conditions, finishes, and permit fees.

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Cost Overview

How Much Does an ADU Cost in California

ADU cost in Southern California typically runs from about $80K for a junior ADU to $350K for a larger detached build, and the answer to how much does it cost depends on a handful of clear factors: the type of unit, the square footage, your finish level, and your site conditions. If you have spent time researching how much does it cost to build an ADU, you have probably run into dozens of vague “it depends” answers. This page gives you the real cost data instead, so you can build a realistic total budget before you commit to a significant investment. Accessory dwelling units can be detached or attached structures, and they serve many purposes, from long term rental income to a home office or multigenerational living space. California allows ADUs between 150 sq ft and 1,200 sq ft, which gives property owners meaningful flexibility. Los Angeles homeowners are a primary market for ADUs in Southern California, and understanding your construction costs upfront is the first step toward a smart build. Whatever you have heard an ADU called, a granny flat, an in-law unit, a casita, or a guest house, the cost to build follows the same drivers, and Renova Built handles the entire process for you under one contract.

Cost by Size

ADU Cost by Square Footage

Square footage is the single biggest cost driver for any ADU project. These are typical 2026 total cost ranges for detached ADUs in our Southern California service area, based on standard-to-mid-level finishes and average site conditions.

Size	Typical total cost
500 sq ft detached	$180K to $220K
600 sq ft detached	$215K to $245K
750 sq ft detached	$250K to $300K
1,000 sq ft detached	$320K to $360K
1,200 sq ft detached	$350K to $380K

These ranges also depend on your floor plan and layout.

Your final pricing depends on site conditions, the finishes you choose, and permit fees. The cost per square foot decreases with larger units because fixed costs like permitting, utility connections, site preparation, and foundation work get spread across more square footage. A 1,200 sq ft ADU does not cost twice as much as a 600 sq ft unit even though it is twice the size. Smaller ADUs offer a lower total investment but a higher cost per square foot, while larger units require more materials and more labor time yet deliver better economics per square foot and stronger rental income potential. High-quality finishes and custom materials can raise the total cost, and premium selections like custom cabinetry, stone countertops, and high-end appliances can push pricing above these ranges. For a detailed walkthrough of the build itself, see our ADU construction guide.

Cost by Type

ADU Cost by Type

The type of ADU you choose creates real differences in your total budget. Here is what each option typically costs in our service area and the trade offs involved. Detached ADUs carry the highest cost, while junior ADUs and garage conversions reuse existing structure for the best value.

ADU type	Typical range
Detached ADU	$180K to $390K
Garage conversion ADU	$150K to $200K
Junior ADU (JADU)	$110K to $200K

Detached ADU Cost

Detached ADUs are the most popular option and represent the highest investment, roughly $180K to $390K depending on size and finishes. They require a separate foundation, independent utility connections, a complete roof system, and full structural construction, and in return deliver the most privacy and the strongest rental income potential. Cost drivers include site conditions, utility distance from the main house, and foundation work complexity. See our detached ADU page.

Junior ADU (JADU) Cost

A JADU is capped at 500 sq ft and can be built inside your existing home or as a new attached unit, with a separate entrance and its own kitchen. Cost range is roughly $110K to $200K, the most affordable ADU option, because a JADU can reuse existing structure and its utilities can connect directly to the main house. The small footprint keeps construction costs low, though electrical work, plumbing additions, and code-required upgrades still apply.

Garage Conversion Cost

Converting an existing garage into a living unit typically costs $150K to $200K. Garage conversion ADUs reuse the existing garage slab, walls, and roof for real cost efficiency. The biggest variables are the condition of the existing structure and the scope of required upgrades, since many older garages need an electrical panel upgrade, new plumbing, insulation, and HVAC installation. See our garage conversion cost page.

No Surprises

Why Our ADU Cost Estimates Are Different

Most homeowners get burned not by the construction costs themselves but by the surprise expenses that pile up after a project starts. A contractor quotes one number, then change orders, permit delays, and utility connection fees push the final cost tens of thousands beyond the original total budget. We take the opposite approach so there are no hidden fees and no budget overruns.

All-inclusive pricing, so every estimate covers design fees, permit costs, Title 24 energy compliance, and construction with no line item hidden or deferred
Fixed price contracts, so your contract price is your final cost, with no change orders that inflate your bill mid-project
In-house team, so you avoid stacked subcontractor markups and inflated labor costs
Licensed CSLB contractor, B #1149349, with transparent pricing backed by proper licensing, bonding, and insurance
Free site assessment before you commit a dollar, with an accurate cost breakdown based on your actual site conditions

Renova Built reviewing a fixed-price ADU cost breakdown in Los Angeles

Cost Calculator

Estimate Your ADU Cost

Get a quick ballpark for your build. Choose your size, layout, and finish level and this calculator returns an estimated cost range in seconds. It is a planning tool, not a quote, and your firm price comes from a free consultation.

Size (sq ft) Bedrooms Bathrooms Finish level Kitchen

Estimated cost range $180K to $195K

This is a rough estimate to help you plan. Your exact price depends on site conditions, design, and finishes. Contact Renova Built for a firm quote. CSLB License B #1149349.

Los Angeles

ADU Cost in Los Angeles

Several factors make Los Angeles one of the more expensive ADU markets in California, and understanding these LA-specific cost drivers helps you build a realistic budget. Permitting fees for ADUs vary significantly depending on the municipality, and the LADBS permitting process often runs a few months from submission to approval, with each correction round adding time and potential rework costs. These are real considerations for any property owner planning a build here.

Seismic and structural requirements, since Los Angeles standards add engineering and construction costs that do not apply in many other markets
Title 24 energy compliance, which requires all-electric ADU systems with heat pumps and enhanced insulation, raising upfront construction costs but lowering long-term operating expenses
Local labor costs and material costs, which reflect one of the most competitive markets in the state
Utility infrastructure, since many older LA homes need an electrical panel upgrade, sewer lateral replacement, or a new water meter, which can add several thousand dollars
Difficult terrain in hillside neighborhoods, where retaining walls, geotechnical reports, and specialized foundation work can push project costs above flat-lot estimates

Detached ADU under construction in a Los Angeles neighborhood by Renova Built

Rental Income

ADU Rental Income Expectations

One of the strongest reasons to build an ADU is the ability to generate rental income. These are typical monthly ranges across Southern California in 2026, not a guarantee, since actual rent depends on size, neighborhood, and finish level. In Los Angeles County a permitted ADU typically rents in the range of $2,200 to $4,500 a month, in Orange County roughly $2,500 to $4,200 a month, and in San Bernardino County around $1,800 to $3,200 a month, where lower construction costs can improve overall returns. Long term rental income provides the most predictable cash flow, and in many scenarios the annual rental income covers or exceeds ADU financing costs. A permitted unit can add meaningful monthly income to a household budget, though every property and market is different. Use the calculator above to run your own numbers, and remember that a vacancy allowance and a maintenance reserve give you a more honest picture of your ADU’s financial performance than gross rent alone.

Short-Term Rental

ADU as a Short-Term Rental or Airbnb

In areas where short-term rentals are permitted, an ADU can earn more than a long term lease, and some owners see meaningfully higher gross income from nightly stays. That upside comes with more turnover, more management, and more variable occupancy, so the net result depends heavily on your neighborhood and how the unit is run. Local regulations vary significantly. Some Los Angeles neighborhoods restrict or prohibit short-term rentals, and rules change, so verify your city’s specific requirements before you build a financial plan around Airbnb income. A safe approach is to make sure the numbers work as a standard long term rental first, then treat any short-term premium as upside rather than the base case.

ROI Calculator

ADU Return on Investment Calculator

Model your own numbers. Enter your estimated build cost, monthly rent, and financing terms to see your estimated loan payment, rental income, and net monthly cash flow. Figures are for planning only, not a quote.

ADU type / size

Estimated build cost ($)

Estimated monthly rent ($)

Down payment %

Interest rate %

Term (yrs)

Est. monthly loan payment$0

Est. monthly rental income$0

Est. net monthly cash flow$0

Enter your numbers to see an estimated payback timeline.

Sample figures for planning only, not a quote or a guarantee. Actual costs, rents, and rates vary. Estimated loan payment assumes standard amortization on the financed amount and does not include taxes, insurance, maintenance, or vacancy.

Permit Fees

ADU Permit Cost

Permit costs are a real part of any ADU project, and many homeowners underestimate them. Here is a transparent cost breakdown of what to expect, all of which is included in our fixed price rather than billed separately.

Permit item	Typical cost
Building permit fees (Los Angeles)	$3K to $6K
Plan check fees	$1.2K to $3K
Utility connection fees	$2.5K to $6.5K
Design and architectural fees (custom)	$15K to $25K
Impact fees (units under 750 sq ft)	Often waived

Permit costs vary by city and can be significant across Southern California municipalities, and some cities waive impact fees for smaller ADUs, typically under 750 sq ft. Soft costs like design, engineering, and Title 24 compliance typically account for 10 to 20 percent of the total budget, while hard costs make up 80 to 90 percent. ADU permits require compliance with local zoning laws, and submitting incomplete applications triggers correction rounds that cost both time and money. Renova Built handles all permitting as part of your contract price, so your total cost stays predictable. For the full walkthrough, see our ADU permits guide.

The Bottom Line

Is an ADU Worth It?

For most homeowners in Southern California the answer is yes, but the financial case depends on your specific numbers. A permitted ADU typically adds value that reflects its build cost, and once rental income is documented the value it adds can rise further. Beyond the return, a well-built ADU adds flexible living space that appeals to future buyers in a market where extra square footage is at a premium. These are typical outcomes, not a guarantee, since every property and market is different. The practical math comes down to monthly income versus loan payments, your break-even timeline, and the tax advantages of a rental unit, including depreciation and deductible expenses. It is wise to set aside a contingency fund of 10 to 20 percent for unexpected costs, which protects your investment from unforeseen costs like soil conditions, utility upgrade requirements, or material price increases. Housing a family member in an in-law unit can also eliminate their rent and save on temporary housing, which changes the equation entirely.

Finished detached ADU adding value to a Los Angeles property by Renova Built

Financing

ADU Financing Options Overview

A significant investment like an ADU calls for the right financing structure. These are the primary financing options available to Southern California property owners, and we help you weigh them at your free consultation.

Home Equity Line of Credit

Access your home equity with flexible draw terms, often the simplest path for homeowners with substantial equity, so you draw only what the build needs.

Construction-to-Permanent Loans

Purpose-built for new ADU construction, this converts from a construction loan to a standard mortgage on completion, avoiding double closing costs.

Cash-Out Refinancing

Replace your existing mortgage with a larger one and use the difference to fund your ADU project, best when current rates are favorable.

Combined Approaches

Many homeowners combine options, such as a HELOC for soft costs and design fees while securing a construction loan for the build itself.

Impact Fee Savings

California law waives impact fees for ADUs under 750 sq ft, which adds real financial flexibility on smaller builds. See our ADU financing overview for the full breakdown.

Granny Flats & In-Law Units

Granny Flat & In-Law Unit Cost

A granny flat and an in-law unit are everyday names for the same thing California code calls an ADU, so their cost to build follows the same ranges above. The name usually reflects who the space is for, an aging parent or an adult child, rather than a different set of rules. A granny flat built as a small detached unit falls in the detached ADU range, while an in-law unit created inside your main house lands in the more affordable JADU range of roughly $110K to $200K. For many families, an in-law unit or granny flat is about more than construction costs. Housing a family member on your own property can eliminate their rent and can save meaningful money each year compared with temporary housing or a separate apartment lease. Because the unit is permitted and self-contained, it also adds long-term flexibility and can generate rental income later if your needs change. Whatever you call it, we build to the ADU code standard so the finished space is fully permitted, and final pricing depends on site conditions, finishes, and permit fees.

Free ADU Consultation

Get Your Free ADU Cost Estimate

Stop guessing about ADU cost and start working with real numbers. Tell us about your property and we will reach out, usually within one business day, with a detailed, no-obligation cost breakdown tailored to your ADU type, site conditions, and budget goals. No hidden fees, no vague estimates. Call (818) 968-2981 or send your details.

ADU Cost FAQ

ADU Cost Questions, Answered

How much does it cost to build an ADU in California?

ADU cost in Southern California typically runs from about $80K for a junior ADU to $350K for a larger detached build. A 500 sq ft detached ADU runs roughly $180K to $220K and a 750 sq ft detached ADU runs roughly $250K to $300K. Garage conversions land around $150K to $200K and a JADU around $110K to $200K. Your final pricing depends on site conditions, finishes, and permit fees.

What type of ADU is the cheapest?

A junior ADU or a garage conversion is the cheapest way to build an ADU, because both can reuse existing space and structure rather than building a new shell from scratch. A JADU runs roughly $110K to $200K and a garage conversion runs roughly $150K to $200K in our service area. We help you weigh the most cost-effective option for your lot at your free consultation.

What is the most expensive part of building an ADU?

For a detached ADU, the most expensive parts are the foundation, the full structural shell, and independent utility connections, since these do not exist yet and must be built new. Finish level is the next biggest lever, because premium cabinetry, countertops, and appliances can push cost per square foot well above the base range. Site conditions like hillside lots or difficult terrain add foundation and site work costs too.

Is it cheaper to build an ADU or buy a prefab?

It depends on your lot and your goals. A prefab or modular unit can look cheaper on the base module price, but you still pay for the foundation, site preparation, utility connections, permits, and crane placement, which narrows the gap. Renova Built builds site-built ADUs designed for your exact lot dimensions, slope, and zoning, and we give you one fixed price that covers everything so you can compare the true total cost, not just a headline number.

What is the $40,000 grant in California for an ADU?

The CalHFA ADU grant program offered up to $40,000 toward pre-development and closing costs, but that funding is currently exhausted and paused. State ADU policy continues to evolve, so new incentive programs may become available in the future. We keep an eye on current programs and flag any you may qualify for during your consultation.

What are the disadvantages of an ADU?

The main trade offs are the upfront investment, the permitting timeline, and some construction disruption on your property while the unit goes up. Costs and rules also vary by jurisdiction, so a project that is straightforward in one city can be more involved in another. Our fixed-price contract and in-house permitting are built to reduce those downsides and keep your total cost predictable.

How much rental income can an ADU generate?

A permitted ADU in Los Angeles County typically rents in the range of $2,200 to $4,500 a month depending on size, neighborhood, and finish level, with Orange County and San Bernardino County falling into their own typical ranges. These are typical figures, not a guarantee. Use the ROI calculator on this page to model your own build cost, rent, and financing and see your estimated net monthly cash flow.

Does an ADU add to my property value?

A permitted ADU typically adds value that reflects its build cost, and once rental income is documented the value it adds can rise further. It also adds flexible, income-producing square footage that appeals to future buyers. These are typical outcomes and not a guarantee, since every property, neighborhood, and market is different.