"How much is an ADU?" is the first question almost every homeowner asks us. The honest answer is a range, and it depends on three things: what kind of ADU you build, the condition of your lot, and the finishes you choose. Here are the ranges we see on real Los Angeles jobs.
ADU price ranges in Los Angeles
| ADU type | Typical size | Price range |
|---|---|---|
| Garage conversion ADU | 380–800 sq ft | $110K–$220K |
| Junior ADU (JADU) inside the existing home | Up to 500 sq ft | Quoted for your project |
| Detached 1-bedroom | 600–800 sq ft | $230K–$390K |
| Detached 2-bedroom or two-story | 900–1,200 sq ft | $390K–$600K+ |
A Junior ADU (JADU) is a unit of up to 500 sq ft created inside a single-family home; it is not interchangeable with converting a garage. Eligibility is confirmed for your address.
A garage conversion is generally a lower-cost path because the walls, roof and slab already exist. A detached ADU is a brand-new building, so it costs more, but it gives the most privacy and a separate living space.
What's not in the build price
- Architectural and engineering plans: not included in the build price or cost estimate. ADU plans typically cost $6,500–$15,000, quoted separately according to each project’s size, specifications, requirements and difficulty.
- City permit fees: not included in the build price or cost estimate. These depend on what the city charges for your project. WOW processes all permits so you don’t have to worry, and gives you the city's fee receipts.
We handle the permit processing, plan check, Title 24 energy compliance and structural engineering for you.
The three things that move the number most
- Slab condition. For conversions, an old garage slab may need leveling or raising.
- Sewer distance. The farther the ADU is from your sewer line, the more trenching it needs. Older 4-inch sewer laterals sometimes need a new tie-in.
- Electrical panel. Many LA homes still have a 100-amp panel. Adding an ADU often means upgrading to 200 amps.
Other cost drivers: two-story units need a staircase, shear walls and heavier engineering. Hillside lots may need caissons or stepped foundations. A separate utility meter is optional and priced on its own.
How long does an ADU take?
- Design and permits: 3–5 months
- Construction: 4–7 months
- Total, start to keys: about 8–12 months (garage conversions land on the shorter end)
Can the rent pay for it?
Here is an illustration, not a rent, financing or payback promise. The example rental range is $2,000–$3,200 a month, with $2,550 used for comparison. A 500 sq ft detached studio ADU with mid-range finishes has an illustrative build estimate of $230K–$280K, excluding plans and city permit fees. A hypothetical loan of approximately $256,369 over 20 years at 8.5% would have a principal-and-interest payment of about $2,225 a month. That payment excludes loan fees, property taxes, insurance, maintenance, vacancy and other operating costs. The rate is an assumption, not a financing offer. Actual rent and borrowing terms depend on the property, neighborhood and lender; rental income is not guaranteed to cover your total costs.
Long-term rental of a permitted ADU is generally allowed in Los Angeles; we confirm the rules for your address. Short-term rental rules are stricter.
Common questions
Will an ADU raise my property taxes?
Generally, the newly constructed portion is assessed while the existing Prop 13 base is retained, subject to applicable reassessment rules. The county Assessor determines the assessable new value. Rules can change — we confirm them for your address.
Do I need to add parking?
Qualifying garage conversions generally do not require replacement parking, regardless of proximity to transit. Separate ADU parking exemptions apply near qualifying transit, generally within half a mile. Rules can change — we confirm them for your address.
How big can my ADU be?
State law provides a protected pathway for an eligible 800 sq ft ADU despite certain local development standards; this is not a blanket guarantee for every property. Los Angeles commonly allows detached ADUs up to 1,200 sq ft under applicable pathways, and generally applies 4 ft side and rear setbacks to new detached construction. Converted existing structures can have different setback rules. Rules can change — we confirm them for your address.
Get a price for your property
Every lot is different, so the real number comes from a site visit. Call WOW Construction Group at (888) 486-2182 or request a free estimate. We've been building in Los Angeles since 2014. CSLB (Contractors State License Board) #1074656.
