Orange County
Santa Ana ADU rules
Research summary of local ADU rules on file for City of Santa Ana in Orange County. Not a determination for a specific lot.
City or county ADU page
Check any California address for freeCity of Santa Ana rules on file
Local rules recorded in this project for this jurisdiction. Where a city figure on file is stricter than the state baseline on file, both are shown.
Local code
Santa Ana ADU rules are in Municipal Code Sections 41-194 to 41-194.7, last amended by Ordinance NS-3076 (February 4, 2025). ADUs and JADUs are allowed in all zones that allow residential or mixed-use development, and the Planning and Building Agency reviews them ministerially for a fee.
Source: Santa Ana Ordinance No. NS-3076 (Municipal Code Sections 41-194 to 41-194.3, adopted February 4, 2025), 41-194 history note; 41-194.2(A)-(B), accessed 2026-10-19.
How many ADUs
Santa Ana's code and ADU page allow one ADU and one JADU on a lot with a single-family home. State law (Government Code 66323(a)) also allows a converted ADU together with a new detached ADU of up to 800 sq ft and a JADU on a single-family lot, and state law controls where they conflict, so confirm the combination with the city. Existing multifamily lot: conversions of non-livable space from one up to 25% of the units, plus up to eight detached ADUs (not more than the number of existing units). Proposed multifamily lot: up to two detached ADUs.
Source: Santa Ana Ordinance No. NS-3076 (Municipal Code Sections 41-194 to 41-194.3, adopted February 4, 2025), 41-194.2(C)-(G), accessed 2026-10-19.
Size
Minimum 220 sq ft for an ADU or JADU. Maximum 1,000 sq ft for an attached or detached ADU; an attached ADU is also limited to 50% of the main home's habitable space, but can go up to 800 sq ft regardless. When a lot has both an ADU and a JADU, the code limits the ADU to 800 sq ft. JADU maximum 500 sq ft. Conversions of part of the main home or an existing accessory structure have no size limit, and an accessory structure can be expanded by up to 150 sq ft.
Source: Santa Ana Ordinance No. NS-3076 (Municipal Code Sections 41-194 to 41-194.3, adopted February 4, 2025), Table 41-194.3, notes (A)-(D), accessed 2026-10-19.
Height
Detached ADU: up to 2 stories or 20 ft, measured from the lowest adjacent grade to the highest point of the roof. Attached ADU and JADU: same as the main building. Conversions are not subject to height limits.
Source: Santa Ana Ordinance No. NS-3076 (Municipal Code Sections 41-194 to 41-194.3, adopted February 4, 2025), Table 41-194.3, note (E), accessed 2026-10-19.
Setbacks
Side, street side and rear setbacks are 4 ft for an ADU; the front setback matches the main building but an ADU may encroach to allow up to 800 sq ft. Conversions and rebuilds in the same place and size need no setback. A JADU follows the main building's setbacks.
Source: Santa Ana Ordinance No. NS-3076 (Municipal Code Sections 41-194 to 41-194.3, adopted February 4, 2025), Table 41-194.3, notes (F)-(G), accessed 2026-10-19.
Open space, lot coverage and separation
On single-family lots, 1,200 sq ft of usable, continuous open space outside the front yard is required (an area at least 15 ft by 15 ft counts as continuous). A detached ADU must be 15 ft from the main building, and ADUs 5 ft from accessory buildings. Zoning lot coverage applies. Each of these can be reduced or exceeded to allow an ADU of up to 800 sq ft, and conversions are exempt.
Source: Santa Ana Ordinance No. NS-3076 (Municipal Code Sections 41-194 to 41-194.3, adopted February 4, 2025), Table 41-194.3, notes (H)-(K), accessed 2026-10-19.
Parking
One parking space is required for a new ADU unless it is within one-half mile walking distance of public transit, in a historic district, part of the main home or an existing accessory structure, on a street where parking permits are required but not offered to the ADU, within one block of a car share vehicle, a studio with no bedroom, or filed with a new home where one of these applies. Tandem parking is allowed. No replacement parking is required when a garage, carport or parking space is removed or converted, and the demolition permit is issued with the ADU permit.
Source: Santa Ana Ordinance No. NS-3076 (Municipal Code Sections 41-194 to 41-194.3, adopted February 4, 2025), Table 41-194.3, notes (L)-(M), accessed 2026-10-19.
Rentals and addresses
ADUs and JADUs cannot be used as short-term vacation rentals but can be rented for 30 days or more. A separate address is required for the ADU and for the JADU. There is no owner-occupancy requirement for an ADU.
Source: City of Santa Ana ADU/JADU Development Standards page, accessed 2026-10-19.
Residential parking permits
Adding an ADU, JADU or garage conversion reclassifies a single-family home as multifamily for the city's permit parking program, which changes the number of permits allotted. Properties with more than four units do not qualify for parking permits.
Source: City of Santa Ana FAQ: How will an ADU/JADU/garage conversion affect my parking permit eligibility?, accessed 2026-10-19.
Historic properties
ADUs and JADUs must conform to the United States Secretary of the Interior's Standards for the Treatment of Historic Properties.
Source: Santa Ana Ordinance No. NS-2986 (Municipal Code Section 41-194.4, adopted April 7, 2020), 41-194.4, accessed 2026-10-19.
Design guidelines
The code says the city's design guidelines apply to ADUs and JADUs.
Source: Santa Ana Ordinance No. NS-3076 (Municipal Code Sections 41-194 to 41-194.3, adopted February 4, 2025), Table 41-194.3, accessed 2026-10-19.
“Pre-Approved ADU” plans
Santa Ana offers downloadable “Pre-Approved ADU” plan sets for detached ADUs in studio, one-bedroom and two-bedroom sizes and several styles. Projects using them must meet the grading permit exemption requirements and include the grading permit exemption form.
Source: City of Santa Ana “Pre-Approved ADU Plans” page, accessed 2026-10-19.
Before you apply with a city plan set
For applications using the city's plan sets, the city strongly advises a pre-submittal consultation with Planning (planning@santa-ana.org). The submittal includes a title report completed within the last six months (with the parcel map, grant deed and legal description), a site plan at a scale of at least 1 inch = 20 ft, a hold harmless agreement, and the grading permit waiver.
Source: City of Santa Ana ADU process, Step 2: Pre-Submittal, accessed 2026-10-19.
JADU owner-occupancy
Not confirmed how the city applies this today: Santa Ana's code and ADU page require owner-occupancy of the home or the JADU and a recorded covenant for every JADU. Since January 1, 2026, Government Code 66333(b) (as amended by AB 1154) requires owner-occupancy only when the JADU shares sanitation facilities with the home. Check with the city.
Source: City of Santa Ana ADU/JADU Development Standards page, accessed 2026-10-19.
Minimum unit size
Not confirmed: the code sets a 220 sq ft minimum for ADUs and JADUs. State law defines an ADU to include an efficiency unit (Health and Safety Code 17958.1, 150 sq ft minimum), so a smaller unit may be allowed. Check with the city.
Source: Santa Ana Ordinance No. NS-3076 (Municipal Code Sections 41-194 to 41-194.3, adopted February 4, 2025), Table 41-194.3, accessed 2026-10-19.
California state rules on file
The statewide baseline recorded from state law and the HCD ADU Handbook.
Detached size cap described in state law
1,200 sq ft. Recorded in this rules file from Government Code section 66314.
Source: California Government Code section 66314, 66314, accessed 2026-10-16.
Side and rear setback cap for a new ADU
4 ft. Recorded in this rules file from Government Code section 66314, which describes a cap on side and rear setbacks for a new ADU.
Source: California Government Code section 66314, 66314, accessed 2026-10-16.
Setback for a conversion of an existing structure
No additional setback, as recorded in this rules file from Government Code section 66314 for a conversion of an existing structure.
Source: California Government Code section 66314, 66314, accessed 2026-10-16.
Minimum lot size
A city may not impose a minimum lot size for an ADU, as recorded in this rules file from Government Code section 66314.
Source: California Government Code section 66314, 66314, accessed 2026-10-16.
Minimum unit the handbook says cities must allow
At least an 800 sq ft ADU with 4 ft side and rear setbacks. The HCD ADU Handbook (updated March 2026) describes this under section 66321(b)(3).
Source: HCD ADU Handbook, 66321(b)(3); handbook updated March 2026, accessed 2026-10-16.
Detached height described in the handbook
16 ft, or 18 ft or 20 ft in some cases. The HCD ADU Handbook (updated March 2026) describes this under section 66321(b)(4).
Source: HCD ADU Handbook, 66321(b)(4); handbook updated March 2026, accessed 2026-10-16.
Permit decision deadline
60 days. Recorded in this rules file from Government Code section 66317(a)(3): the permitting agency must decide on (approve or deny) a completed ADU application within 60 days when an existing single-family or multifamily dwelling is on the lot. Section 66317(a)(1) says the application is considered ministerially, without discretionary review or a hearing.
Source: California Government Code section 66317, 66317(a)(1), (a)(3), accessed 2026-10-17.
Owner-occupancy requirement
None. Recorded in this rules file from Government Code section 66315: a local agency may not impose an owner-occupancy requirement on an ADU. It may require that the property be used for rentals of terms 30 days or longer. The HCD ADU Handbook (updated March 2026) describes the same rule.
Source: California Government Code section 66315, 66315; HCD ADU Handbook updated March 2026, accessed 2026-10-17.
Parking near public transit
No parking standards within one-half mile walking distance of public transit. Recorded in this rules file from Government Code section 66322(a)(1). Section 66322(a) lists several other cases where parking standards may not be imposed.
Source: California Government Code section 66322, 66322(a), accessed 2026-10-17.
Ministerial categories
The HCD ADU Handbook (updated March 2026) states that Government Code section 66323 sets four ministerial categories. This rules file does not restate those four categories.
Source: HCD ADU Handbook, 66323; handbook updated March 2026, accessed 2026-10-16.
Fire Hazard Severity Zones
If your lot is in a Fire Hazard Severity Zone, the CAL FIRE Office of the State Fire Marshal says in Information Bulletin 25-004 (issued March 3, 2025): “Fire Hazard Severity Zones (FHSZs) should not restrict the development of Accessory Dwelling Units (ADUs). However, additional building standards may be necessary, including but not limited to California Fire Code Chapter 49 and California Building Code Chapter 7A.” State ADU law does not itself bar an ADU there. A city or county may still apply its building code, including wildfire-resistant construction (Gov. Code 66314(d)(8)); require side and rear setbacks “sufficient for fire and safety” for a unit converted under 66323(a)(1); and decline parking in setbacks on specific fire and life safety findings (66314(d)(10)(B)). It may also consider public safety when it designates where ADUs may be permitted (66314(a)). Sprinklers can't be required in an ADU or JADU if the primary residence doesn't need them (66314(d)(12), 66323(d)). Some cities and counties still apply their own fire-zone limits. Where this summary has one, it is listed with the local rules. This summary does not look up your lot. Check the CAL FIRE Fire Hazard Severity Zone map viewer linked from the State Fire Marshal's Fire Hazard Severity Zones page: https://experience.arcgis.com/experience/5065c998b4b0462f9ec3c6c226c610a9
Source: CAL FIRE Office of the State Fire Marshal Information Bulletin 25-004, page 4, issued March 3, 2025; Gov. Code 66314, 66323, accessed 2026-10-20.
State baseline on the directory → · State ADU rules on the homepage →
Can I build an ADU in Santa Ana?
State law sets a baseline for ADUs in Santa Ana, and the local standards on file are listed on this page. Whether a specific lot can add an ADU depends on zoning, utilities, and other site facts this page does not measure. Confirm with City of Santa Ana Planning and Building Agency, or run a free address summary.
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