Everything homeowners ask about building an ADU in Anaheim — answered with 2026 data.
Yes, ADUs are allowed in Every zone that allows single-family or multifamily residential use (AMC 18.38.015.010): RH-1, RH-2, RH-3, RS-1, RS-2, RS-3 and RS-4 (Table 4-B) and RM-1, RM-2, RM-3, RM-3.5 and RM-4 (Table 6-B), plus other zones where accessory to an existing legal home. A JADU needs a lot with an existing or proposed single-family house. Not allowed on a parcel that has used both an SB 9 two-unit development and an urban lot split (18.38.015.0502, 18.38.255.070), or in any area the City Council designates by resolution as lacking sewer capacity (18.38.015.0501); Public Works confirms sewer capacity by letter before plan check in Anaheim, CA. The maximum size for a detached ADU is 1,200 sq ft of habitable area (Table 38-A), subject to AMC 18.04.080.020: all detached accessory structures on the lot combined may not exceed the main house's floor area or the zone's minimum livable floor area (1,700 sq ft in RH-1, RH-2, RH-3 and RS-1; 1,225 sq ft in RS-2, RS-3 and RS-4; required garage space not counted). An 800 sq ft ADU with 4-ft side and rear setbacks must be allowed regardless (Gov. Code 66321(b)). Minimum unit size 150 sq ft. Attached ADUs can be up to The lesser of 50% of the main dwelling's floor area or 1,200 sq ft. Anaheim has an ADU-friendliness score of 7/10. Check our full Anaheim ADU rules page for complete zoning details.
ADU construction in Anaheim typically costs $220,000-$450,000. The cost per square foot averages $300-$500. Garage conversions are more affordable at $90,000-$200,000, while prefab ADUs cost $170,000-$340,000. Permit fees add Building Permit Fees schedule (Exhibit A, Tier 3 Type VB, Residential Category 1, Dwellings and Custom; posted Aug 2026): combined plan check and building permit of $1,677 for the first 500 sq ft plus $213 per extra 100 sq ft up to 1,000 sq ft (about $2,316 for an 800 sq ft ADU), then $2,741 at 1,001 sq ft plus $171 per 100 sq ft (about $3,083 for 1,200 sq ft). Add trade permits (electrical $26 for the first 100 sq ft plus $0.26 per sq ft; plumbing $49 per fixture; $188 minimum per trade permit), Zoning Plan Check $352 and a $114 address fee (Planning fee schedule, Aug 2025). Budget roughly $3,000-$4,500 in city fees for an 800-1,200 sq ft detached ADU before impact and school fees to your budget. See our detailed Anaheim ADU cost guide.
Detached ADUs in Anaheim can be up to 1,200 sq ft of habitable area. Attached ADUs are limited to The lesser of 50% of the main dwelling's floor area or 1,200 sq ft. Junior ADUs (JADUs) have a cap of 500 sq ft maximum, 150 sq ft minimum, built within the walls of the existing or proposed single-family house or attached to a newly built detached ADU (18.38.015.0303, Ord. 6620). Up to 150 sq ft may be added to the house for entry and exit as long as the JADU stays at or under 500 sq ft; it needs an efficiency kitchen and its own exterior door, and may share a bathroom with the house if there is interior access (Table 38-A). Maximum height is Detached ADU of any size: 18 ft plus 2 ft for a roof pitch, or the height of the main dwelling, whichever is greater (Table 38-A). Attached ADU or JADU: the underlying zone's limit (Table 4-F: 25 ft/2 stories in RH-1 to RH-3, 30 ft in RS-3, 35 ft in RS-1, RS-2 and RS-4). Detached ADUs on a multifamily lot: 18 ft plus 2 ft for roof pitch (18.38.015.020). A detached ADU over 800 sq ft must sit at least 10 ft from the main house; conversions of existing structures are exempt from height and separation rules (18.38.015.140). You are allowed up to Single-family lot: one ADU converted from existing or proposed space in the house or an accessory structure, plus one new-construction ADU, plus one JADU, for no more than four units including the main house on a qualifying lot.
Rear setback: 4 ft for any ADU (Table 38-A); a JADU follows the underlying zone. Converting a legally permitted structure needs no setback, and a legal accessory structure may be demolished and rebuilt as an ADU in the same location and dimensions without new setbacks (18.38.015.140). Eaves and roof overhangs must stay at least 12 inches from the property line. Side setback: 4 ft for any ADU (Table 38-A); same conversion and rebuild exemptions as the rear setback, and eaves at least 12 inches from the property line. Detached ADUs on multifamily lots: 4 ft side and rear (18.38.015.020). Front setback: The underlying zone's front setback (Table 38-A). A detached ADU may be no closer to the front property line than the front-most wall of the main house, except an ADU created by converting an existing garage, carport or covered parking structure; the Planning and Building Director may approve a modified front setback, including placing the ADU forward of that wall, where the standard would prevent an 800 sq ft unit (Table 38-A footnote 3, Ord. 6620). An attached ADU above an existing nonconforming structure in the front setback may keep that structure's location and dimensions. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
AMC 18.42.030.070: no space for a studio ADU or any JADU; 1 space for an ADU with one or more bedrooms. No space is required when the ADU is within a half-mile walk of a transit stop, in a designated historic district, inside the existing or proposed house or an existing accessory structure, where street-parking permits are not offered to the ADU occupant, where a car-share station is within one block, where a garage, carport or covered parking is demolished or converted for the ADU, or when the ADU is built together with a new house (18.42.030.0701). No replacement parking is required for a converted or demolished garage, carport or driveway space (18.38.015.140, 18.42.030.0705). A required space in a shared garage must be walled off with its own door for the ADU, and the driveway must be at least 10 ft wide. 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 (the former 18.38.015.125 was deleted by Ord. 6620; Gov. Code 66315). For a JADU, the owner must live in either the house or the JADU only when the JADU shares a bathroom with the house (18.38.015.1101, matching Gov. Code 66333(b) as amended by AB 1154); it is waived when the owner is a government agency, land trust or housing organization. The city records a JADU covenant with the Orange County Recorder before the building permit issues (18.38.015.115; Nov 2025 checklist), and the unit not occupied by the owner may be rented only for 30 or more consecutive days (18.38.015.1102). 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 Anaheim is typically The city must tell you within 15 business days whether the application is complete, each resubmittal gets the same 15-business-day check, and a complete application must be approved or denied within 60 days (18.38.015.1502 to .1504); under Gov. Code 66317(a)(3) as amended by SB 543 (Jan 1, 2026) an application not acted on in 60 days is deemed approved. If the ADU is filed with a permit for a new house, the ADU decision may wait for that permit. ADU Express: review in one to three days and the building permit issued in as little as one day after fees are paid, but the address-eligibility screening beforehand can take a few weeks (city ADU Express and catalogue pages). The Building Division publishes no standard plan-check turnaround. Plan check: Planning reviews zoning compliance inside the Building Division's plan check; plans must meet the 2025 California Building, Residential, Electrical, Mechanical, Plumbing, Energy, Fire and Green Building codes with Anaheim's Title 15 amendments for submittals on or after Jan 1, 2026 (Seismic Design Category D-F, Climate Zone 8). Fire sprinklers are not required in the ADU or JADU if the main house has none (18.38.015.0602). Even a free pre-approved plan may still need a site plan, Title 24 energy forms, structural details and a soils report from a design professional; the catalogue's Notes column says which. Pre-approved plans availability: Yes. The city's Pre-Approved Plan Catalogue lists four free detached plans (Sept 2026): Plan 001 studio 224 sq ft, Plan 002 one-bedroom 499 sq ft, Plan 003 two-bedroom 990 sq ft and Plan 004 three-bedroom 1,199 sq ft, all updated to the Building Code requirements effective July 1, 2024; no prefab or modular plans are listed yet. The plans may be used in standard plan check or through ADU Express, where they cannot be modified and conversions, expansions and attached ADUs are not eligible. Check eligibility by address with the ADU Express Eligibility Tool, then email ADUExpress@anaheim.net with the plan number and meter-spot report.
Average ADU rental income in Anaheim: 1-bedroom units rent for $2,000-$2,700/month, 2-bedroom units for $2,600-$3,200/month. Short-term rentals: No. Anaheim has not allowed any new short-term rental since its 2016 ban; the June 2019 update to AMC Chapter 4.05 keeps existing permitted STRs only, so an ADU cannot be listed for stays under 30 days. Expected ROI: 6-10% gross rental yield on a $250,000-$400,000 detached build at $2,000-$2,700/mo (before taxes, vacancy and financing).
The minimum lot size for an ADU in Anaheim is No minimum lot size (Table 38-A sets none). Lot coverage does not apply to an ADU of 800 sq ft or less; an ADU over 800 sq ft and a JADU must meet the underlying zone's lot coverage (Table 38-A). 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 Anaheim, a garage conversion typically costs $90,000-$200,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
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