Every ADU question California homeowners actually search.

An accessory dwelling unit is a second home on the same lot as a primary residence, with its own kitchen, bathroom, and entrance. California law calls it an ADU; people also say granny flat, in-law unit, backyard home, or casita. There are three kinds: detached (a separate structure), attached (shares a wall with the main house), and converted (built inside an existing garage, basement, or accessory structure).

A junior ADU is a unit of no more than 500 square feet carved out of the existing single-family home or attached garage. It needs an efficiency kitchen and its own entrance but can share a bathroom with the main house. An ADU can be larger, detached, and must have its own bathroom. Full guide: JADU rules.

A stand-alone dwelling in the yard, separate from the main house. It is the type California law protects most: every residential lot is entitled to an 800 square foot detached ADU with four-foot side and rear setbacks that a city cannot deny on lot coverage or floor area grounds. Detached ADUs add the most rent and value. See detached ADU size, setbacks, and cost.

Almost certainly yes. State law lets any lot with an existing or proposed home add at least one ADU (plus a JADU on single-family lots), and cities cannot ban them. The questions that matter are how large, where on the lot, and what it costs, which is what Parcy answers from your address.

Parcy covers any residentially zoned parcel in California, single-family or multifamily. Coverage is deepest in Los Angeles County, Orange County, San Diego, and the Bay Area where county GIS publishes zoning and overlay data. The app is free to download and run.

Two by right: one ADU (detached, attached, or converted) plus one JADU. Some combinations of a converted ADU and a new detached ADU are also allowed. Details in the two-ADU rule.

Under SB 1211 (effective January 1, 2025): detached ADUs up to the number of existing units, capped at eight, plus converted-space ADUs from non-livable areas up to 25% of the existing unit count. A fourplex can add four detached ADUs; a twelve-unit building can add eight plus three conversions. Read SB 1211 explained.

A 2024 California bill that raised the multifamily detached ADU cap from two to eight, kept the 25% converted-space allowance, and stopped cities from requiring replacement parking when uncovered spaces are removed to build an ADU. It applies to lots with existing multifamily buildings.

Yes, but a duplex is capped at two detached ADUs, which was already the rule. SB 1211 changes the math for lots with three or more units.

An ADU needs a primary dwelling, existing or proposed. You can permit a new house and a detached ADU together. For a vacant lot on its own, SB 1123 allows up to ten homes ministerially; that pathway is on Parcy's roadmap.

Every lot gets an 800 square foot detached ADU by right. Cities must allow at least 850 square feet for a studio or one-bedroom and 1,000 square feet for two or more bedrooms. Many cities, including Los Angeles, allow 1,200 square feet. Attached ADUs are limited to 50% of the main house's floor area, with the same minimums.

Four feet from side and rear property lines for a new detached or attached ADU. No setback is required when converting an existing garage or accessory structure in place. Front setbacks follow the zone but cannot block the 800 square foot unit.

Sixteen feet for a detached ADU; eighteen feet on a multifamily lot or within a half mile of major transit, plus two more feet to match the main roof pitch; twenty-five feet or the zone limit for an attached ADU. Many cities allow two-story ADUs above the state minimum.

Not anymore. From 2026, SB 543 measures the state-exempt 800 square feet as interior livable space, so exterior walls and stairs do not count against it.

Yes where the height limit allows it. Two-story detached ADUs fit under the 18-foot limit near transit or on multifamily lots and under local limits in many cities. ADUs over garages are common in Los Angeles and San Diego but cost more because of structural and fire separation work.

It depends more than any other question on this page. Rough 2026 ranges: JADU $60,000 to $140,000; garage conversion $90,000 to $180,000; prefab or pre-approved detached $180,000 to $300,000; site-built detached 800 to 1,200 square feet $280,000 to $450,000; two-story or over-garage $400,000 to $600,000 and up. Finish level, slope, utilities, and your city can move any of these by $100,000. Full breakdown: ADU cost in California.

Roughly $300 to $500 per square foot for new detached construction in Southern California and the Bay Area, $200 to $350 for garage conversions, and $150 to $300 for a JADU. Small units cost more per foot because kitchens and bathrooms do not shrink.

Typically $90,000 to $180,000 for a two-car garage, driven by the slab, insulation, plumbing runs, and whether the city requires a separate electrical service. It is the fastest and cheapest path to a rentable unit.

An 800 square foot detached ADU runs roughly $280,000 to $380,000 site-built in 2026; 1,200 square feet runs $380,000 to $480,000. Prefab can come in lower. Parcy prices your lot with local per-square-foot data rather than a state average.

Parcy is one. Enter a California address, place an ADU on the parcel, set bedrooms, stories, and finish level, and the app returns build cost, rent, value added, and return on cost from local data. It is free on iPhone and Android.

ADUs under 750 square feet are exempt from impact fees statewide. Larger units pay fees proportional to the main house. From 2026, ADUs and JADUs under 500 square feet are also exempt from school fees.

Most owners use a HELOC or cash-out refinance on the main home. Renovation and construction loans that count projected ADU rent are common, and the CalHFA ADU grant has periodically offered up to $40,000 for pre-development costs when funded. Multifamily owners typically use a construction loan sized on stabilized income and refinance after lease-up.

Yes. Fannie Mae, Freddie Mac, and FHA all allow a share of ADU rent (usually 75%) to count as qualifying income on a purchase or refinance of a property with a permitted ADU, with an appraisal or lease to support it.

Yes. Every ADU needs a building permit, and a JADU needs a permit plus a recorded deed restriction. The good news is that approval is ministerial: no public hearing, no discretionary review, no CEQA.

The city must approve or deny a complete application within 60 days. Under SB 543 (2026), it must tell you whether the application is complete within 15 business days, and if it misses that deadline the application is deemed complete. Plan check comments and resubmittals are the usual source of delay.

Plan check and permit fees typically run $5,000 to $15,000 depending on the city and unit size, on top of design and engineering. Impact fees are waived under 750 square feet.

Confirm zoning and buildable area, get plans and structural engineering (or use a city pre-approved plan), submit to the building department, respond to plan check comments, pull the permit, build with inspections, and get a certificate of occupancy. Parcy handles the first step in seconds; our consult team can run the rest.

Under AB 1332, every California city and county must publish pre-approved ADU plan sets and act on an application using one within 30 days. They cut design cost and plan check time, at the price of less customization.

Usually yes. Under AB 2533, a city cannot deny a permit for an ADU or JADU built before January 1, 2020 unless it is substandard under the health and safety code, and it must waive impact and connection fees. See legalizing an unpermitted ADU.

No. AB 976 permanently removed owner-occupancy requirements for ADUs. JADUs required it until 2026; under AB 1154 it now applies only when the JADU shares a bathroom with the main house.

State law requires that an ADU be rented for terms of 30 days or longer. Short-term rental is not allowed for ADUs permitted under the state statute, and most cities enforce it.

At most one space per unit, and none at all within a half mile of major transit, for converted garages, or in historic districts. SB 1211 also bars replacement-parking requirements when uncovered spaces are removed for an ADU on multifamily lots.

In 2026, a new two-bedroom detached ADU in Los Angeles or Orange County rents for roughly $2,800 to $3,800 a month, a one-bedroom $2,200 to $2,900, and a studio JADU $1,600 to $2,100. Bay Area rents run higher. Parcy pulls live comps near your lot.

Only if your city has adopted an AB 1033 ordinance allowing ADU condominiums. Where it applies, the ADU gets its own parcel number and can be sold and financed on its own. See AB 1033.

Yes, but how much depends on unit count. At one to three units the ADU is a comps adjustment and usually trails build cost for a year or two. At five or more units the rent is capitalized directly: a $3,000 ADU adds roughly $400,000 at a 5.5% cap rate. Read how appraisers value ADUs.

SB 543 (15-business-day completeness review with deemed-complete, interior measurement of the 800 square foot exemption, school fee exemption under 500 square feet), AB 1154 (JADU owner-occupancy only when a bathroom is shared), and AB 462 (60-day coastal permits and disaster-area ADU occupancy). Full list: California ADU laws 2026.

The 2021 law that lets owners of single-family lots split the lot and build up to two homes on each half, ministerially, up to four homes total. Each new parcel must be at least 40% of the original and 1,200 square feet, and the owner signs a three-year occupancy affidavit. SB 9 analysis is coming to Parcy; read SB 9 explained.

ADUs keep one parcel, need no occupancy affidavit, and get you to three units on a single-family lot. SB 9 creates separate fee-simple lots you can sell individually. Many lots do better with ADUs; SB 9 wins when the goal is to sell the new homes.

SB 684 allows ministerial small-lot subdivisions of up to ten homes on multifamily-zoned lots under five acres; SB 1123 extends it to vacant single-family lots from July 2025. New parcels can be as small as 600 square feet. Guide: SB 684 and SB 1123.

The 2025 transit-oriented upzoning law, effective July 1, 2026, that overrides local height and density limits within a half mile of major transit stops in California's largest counties. It mainly affects multifamily redevelopment and land value. Guide: SB 79.

Not yet. Parcy launches with California ADU law: detached, attached, and converted ADUs, JADUs, and SB 1211 for multifamily lots. SB 9, SB 684, SB 1123, SB 79, and density bonus are next on the roadmap. The law index tracks every bill.

Cities can adopt objective standards, but they cannot go below the state floor: the 800 square foot unit, four-foot setbacks, 60-day approval, no owner-occupancy, and the parking limits all apply regardless of local code. Since 2025 HCD can void a non-compliant ordinance, and AB 712 adds fines.

Yes. Download it on iPhone or Android, enter an address, and run the analysis at no cost. Some advanced unlocks use credits.

Rents come from live comps near the lot, build costs from local per-square-foot pricing by ADU type, and valuations from the method a lender would use at that unit count. They are estimates for deciding whether a project is worth pursuing, not a bid or an appraisal. Verify with a licensed architect and your planning department before you build.

Yes. Drag units anywhere in the buildable area, resize them, change bedrooms, stories, and finish level, and the cost, rent, value added, and return on cost update as you edit.

Save scenarios, compare up to five properties side by side, and export a PDF to hand to a lender, partner, or architect.

Our development team runs your parcel through every applicable pathway, walks the numbers with you, and tells you plainly whether it pencils. If it does, we can design, permit, and build it, and we are currently able to defer construction costs until the end of the project. Book a consult.