Everything homeowners ask about building an ADU in Los Angeles — answered with 2026 data.
Yes, ADUs are allowed in Every zone where a single-family or multifamily dwelling is a permitted use, on any lot with an existing or proposed dwelling (LAMC 12.22 A.33(c)(3) and (c)(6); ZA Memo 143 Q.2, Q.29): all R, RD, RW, RE, RS, RA and A zones plus commercial zones that list residential uses, but not where housing is allowed only as a caretaker unit (M zones). One exception: a city-ordinance ADU on a lot that is in BOTH a Very High Fire Hazard Severity Zone and a Hillside Area is barred unless it is in the Northeast LA or Silver Lake-Echo Park-Elysian Valley plan area or fronts a 20-ft-wide improved street (12.22 A.33(c)(4)); state-law units under Gov. Code 66323 (800 sq ft detached, conversions, JADUs) are exempt from that bar (ZA Memo 143 Q.42). In the Coastal Zone a Coastal Development Permit is still required and adds a separate City Planning filing (12.22 A.33(k); ZA Memo 143 Q.23). Check ZIMAS for zone, Hillside, VHFHSZ, HPOZ and Coastal flags in Los Angeles, CA. The maximum size for a detached ADU is 1,200 sq ft under the city ordinance (12.22 A.33(d)(1)), subject to the lot's floor-area (RFA/FAR) and lot-coverage limits; the state-law option (Gov. Code 66323(a)(2)) is 800 sq ft, and no floor-area, lot-coverage, open-space, front-setback or lot-size rule may block an 800 sq ft unit with 4-ft side and rear setbacks (12.22 A.33(c)(1)(iii); Gov. Code 66321(b)(3)). Square footage is measured as Building Code gross floor area inside the exterior walls (ZA Memo 143 Q.3). Conversions of an existing garage or accessory building have no size cap and may add up to 150 sq ft for entry and exit (66323(a)(1)). Attached ADUs can be up to 50% of the existing primary dwelling's floor area for a city-ordinance attached ADU, with no percentage cap when the house is being built at the same time; the city may never deny an attached ADU under 850 sq ft, or under 1,000 sq ft with more than one bedroom. Los Angeles has an ADU-friendliness score of 9/10. Check our full Los Angeles ADU rules page for complete zoning details.
ADU construction in Los Angeles typically costs $220,000-$400,000. The cost per square foot averages $300-$500. Garage conversions are more affordable at $100,000-$200,000, while prefab ADUs cost $120,000-$350,000. Permit fees add No flat ADU fee. The LADBS building permit fee is set by construction valuation under LAMC 91.107 Table 1-A: for a valuation between $100,000 and $500,000 the codified base is $395 plus $3.50 per $1,000 (about $1,445 on $300,000, or about $2,384 as a combined building-mechanical permit at 165% of that figure), plus plan check at 90% of the permit fee (91.107.3.1.1), a 2% plan-maintenance fee (91.107.4.3), a fire-hydrant fee of 0.22% of valuation on jobs of $50,000 or more (91.107.4.4), state seismic and green-code surcharges, and the City Planning General Plan Maintenance Surcharge, raised from 7% to 10% on June 9, 2026 (CF 09-0969-S4). Table 1-A amounts are indexed to CPI every July 1 (91.107.1.1), so run the LADBS Permit Fee Calculator for the current total. LAUSD developer fees of $5.38 per sq ft apply to an ADU larger than 500 sq ft from August 11, 2026 (about $4,300 on 800 sq ft) to your budget. See our detailed Los Angeles ADU cost guide.
Detached ADUs in Los Angeles can be up to 1,200 sq ft under the city ordinance. Attached ADUs are limited to 50% of the existing primary dwelling's floor area for a city-ordinance attached ADU, with no percentage cap when the house is being built at the same time; the city may never deny an attached ADU under 850 sq ft, or under 1,000 sq ft with more than one bedroom. Junior ADUs (JADUs) have a cap of 500 sq ft, entirely within the walls of an existing or proposed single-family house including an attached garage (LAMC 12.03 definition; Gov. Code 66333). Needs its own exterior entrance and at least an efficiency kitchen; may share a bathroom with the house; one per lot. No parking and no separate utility connection fee (ZA Memo 143 Sec. II.B). Maximum height is State-law detached ADU: 16 ft; 18 ft within a half-mile walk of a major transit stop or high-quality transit corridor, plus 2 ft (20 ft) if the roof pitch matches the main house; 18 ft on a lot with a multistory multifamily building (Gov. Code 66321(b)(4); ZA Memo 143 Table 1, Q.34, Q.38). City-ordinance detached ADU: the zone and height-district limit for the lot, up to 2 stories (12.22 A.33(d)(2)). Attached ADU: the zoning height limit or 25 ft, whichever is lower (Table 2). Height is measured the same way as any other building in the zone (Q.5). You are allowed up to Single-family lot: one attached or conversion ADU on a qualifying lot.
Rear setback: 4 ft for a new detached ADU or a new addition (12.22 A.33(c)(8); Gov. Code 66323(a)(2)). None for an ADU created inside an existing house, garage or accessory building, or rebuilt in the same location and dimensions. Side setback: 4 ft for new construction, including the added portion of a unit built over an existing garage; none for a same-footprint conversion or rebuild. If the zone's own side yard is under 4 ft, the smaller figure applies (ZA Memo 143 Table 1 note 7). Front setback: A city-ordinance detached ADU must sit behind the house, not between the house and the street, unless the lot is a through lot or the unit is added to an existing front-yard garage or accessory building (12.22 A.33(d)(3)). The zone's front yard applies to ordinance ADUs, but it cannot be used to block an 800 sq ft ADU with 4-ft side and rear setbacks, and no front setback may be imposed on state-law units under Gov. Code 66323 (66321(b)(3); ZA Memo 143 Q.37). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
One space per city-ordinance ADU, waived when the lot is within a half-mile walk of any bus or rail stop, within a block of a car-share pick-up point, in a National or California Register district or an HPOZ, or when the ADU is inside the existing house or an accessory structure (12.22 A.33(c)(12)(i)); state law adds waivers where street parking permits are not offered to the ADU occupant or the ADU is permitted with a new house (Gov. Code 66322; ZA Memo 143 Table 1 note 9). State-law units under Gov. Code 66323 (800 sq ft detached, conversions, multifamily units) and JADUs need no parking at all. Required parking may be tandem or in a yard on an existing driveway, and no replacement parking is required when a garage or carport is converted or demolished for an ADU (c)(12)(iii). Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required for an ADU (Gov. Code 66315 as amended by AB 976, permanent). A JADU requires owner-occupancy of the house or the JADU only when the JADU shares a bathroom with the house (Gov. Code 66333(b) as amended by AB 1154, effective January 1, 2026); every JADU still records a deed restriction against separate sale (66333(c); ZA Memo 143 Sec. II.B). ADUs may not be sold separately from the house except under the Gov. Code 66341 nonprofit exception (12.22 A.33(h)(3)). Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Los Angeles is typically The city must tell you within 15 business days whether the application is complete and must approve or deny it within 60 days of a complete application, or it is deemed approved (Gov. Code 66317(a) as amended by SB 543, in force January 1, 2026; LAMC 12.22 A.33(c)(2); ZA Memo 143 Q.24). If the ADU is filed with a new house, the ADU permit may wait for the house permit. LADBS publishes no average ADU plan-check turnaround; the Standard Plan Program is described only as shortening plan check. Plan check: Electronic plan check through LADBS ePlanLA or in person at a Development Services Center; LADBS reviews building, residential and green code and zoning compliance in one ministerial review, and only conditions affected by the ADU that threaten health or safety must be corrected (Gov. Code 66322(b); ZA Memo 143 Q.25-Q.26). Fire sprinklers are not required unless the main house needs them (12.22 A.33(c)(10)); a new detached ADU must have solar panels under the state energy code (LADBS ADU page); the Fire Department requires a separate address for every unit including a JADU; a JADU needs an efficiency kitchen and, if it shares a bathroom, an interior door to the house. Pre-approved plans availability: Yes. LADBS's ADU Standard Plan Program listed 83 plans in its April 2026 list, 79 approved and 4 pending, from a 200 sq ft studio to 1,200 sq ft three-bedroom units, 8 of them two-story; one 455 sq ft one-bedroom plan is owned by the City and free to use, the rest are licensed from their designers. LADBS still reviews site-specific items (zoning, foundation) for each lot, and roof-deck plans may need extra setbacks in some zones.
Average ADU rental income in Los Angeles: 1-bedroom units rent for $2,050-$2,550/month, 2-bedroom units for $2,600-$3,350/month. Short-term rentals: Effectively no. Expected ROI: 6-10% gross rental yield on a $220,000-$400,000 detached build at $2,050-$3,350/mo (before taxes, vacancy and financing); a $100,000-$200,000 garage conversion renting at 1-bedroom rates yields more.
The minimum lot size for an ADU in Los Angeles is No minimum lot size for any ADU (12.22 A.33(c)(1)(i); Gov. Code 66314(b)(1)); a substandard lot from an old illegal split is not grounds for denial (ZA Memo 143 Q.16). This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Los Angeles, a garage conversion typically costs $100,000-$200,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
Tell us about your project and we'll pass it to ADU builders serving Los Angeles. Free, no obligation — you choose who to work with. We don't have builders in every area yet; if nobody covers yours, we'll email you to say so.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
Just browsing? Search ADU builders near you by ZIP code.