ADU guides

• How long does an ADU permit take in Los Angeles?Median days from application to ADU permit in Los Angeles by type and year, the state's 60-day rule, other cities, and how long building takes.
• How much does an ADU cost in Los Angeles?What Los Angeles homeowners declared as the value of their ADU on building permits, by type and year, and why real costs run higher.
• ADU types explained: detached, garage conversion, JADUDetached ADU, attached ADU, garage conversion and junior ADU (JADU) explained, with how popular, fast and costly each is in Los Angeles.
• How long does it take to build an ADU?How long ADUs take from building permit to the city's final sign-off, by type, year and neighborhood, and how many get finished, from permit records.
• How long does an ADU permit take in Ventura County?Median days from application to ADU permit in each Ventura County city and the unincorporated county, approved projects waiting, and the state's 60-day rule.
• Converting a garage to an ADU in Los AngelesGarage conversion ADUs in Los Angeles: the parking rule, how many are permitted, permit and build times, declared costs, and where in the Valley they're most common.
• Junior ADUs (JADUs) in Los AngelesJunior ADU rules (500 square feet, inside the house, owner occupancy) and how JADUs compare in Los Angeles: permits, permit and build times, declared costs.
• Building a detached ADU in Los AngelesDetached ADUs (backyard cottages) in Los Angeles: height and size rules, how many are permitted, permit and build times, declared costs, by neighborhood.
• California ADU rules: can I build an ADU?What California law lets you build: an ADU, a junior ADU and a detached ADU on most home lots, and the state's limits on size, height, setbacks, parking and fees.
• Why ADU projects stall: what the permit records showHow many ADU permits in Los Angeles get finished, stay open for years or expire, by year and neighborhood, and Ventura County projects approved but never permitted.
• Legalizing an unpermitted ADU in Los AngelesLos Angeles' AB 2533 amnesty for ADUs built without permits before 2020: who qualifies, proof of age, steps, fees, and what state law guarantees.
• Applying for an ADU permit in Ventura County, city by cityOfficial ADU pages for every Ventura County city and the county, what each offers (pre-approved plans, portals, checklists), and their permit counts and times.
• Is an ADU worth it? Rent and cost, by the numbersHUD's Fair Market Rents where ADUs are being built in Los Angeles and Ventura County, next to declared ADU costs, with the math and what it leaves out.
• ADU utilities and solar: power, water, sewerElectric meters and power lines (LADWP, SCE), water and sewer connections, the solar requirement for new ADUs under the 2025 Energy Code, and utility timelines.
• ADUs on hillside, fire-zone, historic and coastal lots in Los AngelesHow Los Angeles treats ADUs in Hillside Areas and very high fire hazard zones, historic districts (HPOZs) and the Coastal Zone, and what state law protects.
• Renting out an ADU in Los Angeles and Ventura CountyWhen an ADU triggers LA's rent control, rent increase caps, just-cause eviction rules, registration, short-term rental limits and renting to Section 8 voucher holders.
• Insuring an ADUHow a homeowners policy covers attached and detached ADUs, why the 10% other-structures limit matters, renting it out, and the FAIR Plan in fire zones.
• What changed in California ADU law in 2025 and 2026The main California ADU law changes in effect in 2025 and 2026, and the two taking effect January 1, 2027, in plain English with links to each bill.
• SB 9 lot splits and two-home projects in Los AngelesWhat California's SB 9 allows (two homes and a lot split on single-family lots), which lots qualify, how it limits ADUs, and how Los Angeles handles it.
• Adding ADUs to an apartment building or duplexHow California's ADU law lets owners of duplexes and apartment buildings convert unused space and build up to eight detached ADUs, and where cities differ.
• Does an ADU increase property value?What research on Los Angeles and California appraisals shows about ADUs and home value, how appraisers handle an ADU, unpermitted units, and property taxes.
• How to pay for an ADU: loans, grants and rentHow homeowners pay for an ADU: refinancing, home equity, renovation loans, counting ADU rent to qualify, the status of ADU grants in 2026, and property taxes.
• ADU fees in Los Angeles and Ventura CountyWhich ADU fees California waives (impact fees up to 750 sq ft, school fees under 500), what you still pay in Los Angeles and Ventura County, and coastal and hillside lots.
• Pre-approved ADU plans in Los Angeles and Ventura CountyLA's ADU Standard Plan catalog and how the program works, the state's 30-day rule, and which Ventura County cities offer free pre-approved plans.
• How to choose an ADU builder in Southern CaliforniaCheck the contractor's license, see their finished ADUs, compare quotes and know California's down-payment limit before you hire an ADU builder.

The numbers in these guides come from public building-permit records: City of Los Angeles Department of Building and Safety permits, and the annual reports other cities file with the state. Legal and program points summarize the laws, the state's ADU Handbook and each agency's published rules, and link to them. Rules change and every lot is different, so treat the guides as a starting point and confirm details with your city.

Looking for your area? Browse ADU permits by city and neighborhood, or search an address on the map.