Building an ADU in Santa Ana

Which rules apply in Santa Ana

Santa Ana's ADU rules are in section 41-194 and the sections after it of the zoning code. They were last amended by Ordinance NS-3076 in February 2025. The city's ADU/JADU Development Standards page summarizes them.

The city reviews ADUs ministerially: the executive director of the Planning and Building Agency approves or denies them based on whether the application is complete, meets the code, and the review fee has been paid. The code says applications that are incomplete or don't fully conform "will be rejected."

State law sets the floor for what any California city must allow; see our California page. Where the city's code is stricter than state law as the state housing agency (HCD) explains it, this page says so. Ask the Planning Division at (714) 647-5804 how those rules apply to your lot. [1][2][5]

What you can build

ADUs are allowed in all zones where homes or mixed-use development are allowed, including the R1, R2, R3 and R4 zones and specific plans that allow homes. Check your zone with the city's property information search. There's no minimum lot size.

• Single-family lot: the code allows no more than one ADU, plus one JADU. HCD's handbook says state law requires cities to allow one ADU converted from existing space, one JADU and one new detached ADU of up to 800 sq ft with 4-foot side and rear setbacks on the same lot. Ask Planning before you design around more than one ADU.
• Existing apartment building: ADUs converted from non-living space in the building (at least one, up to 25% of the units), plus up to eight detached ADUs, not more than the number of existing units. The city's example: a 12-unit complex can add eight detached and three converted ADUs, 11 in all.
• Lot with a proposed apartment building: up to two detached ADUs.
• No JADUs on lots with apartment buildings or with more than one detached house.

[1][2][3][5][6]

Size, height and setbacks

These standards come from Table 41-194.3 of the code.

• Size: at least 220 sq ft, up to 1,000 sq ft for an attached or detached ADU. An attached ADU also can't be more than 50% of the house's living space, except that an 800 sq ft attached ADU is always allowed. If the lot will have both an ADU and a JADU, the ADU is capped at 800 sq ft. Converting space inside the house or an existing accessory structure has no size limit, and an accessory structure can grow by up to 150 sq ft when converted.
• Height: a detached ADU can be two stories, up to 20 feet. An attached ADU can be as tall as the zone allows for the house. Conversions have no height limit.
• Setbacks: 4 feet from side, rear and street-side lot lines. The front setback matches the house, but an ADU of up to 800 sq ft can encroach into it. Conversions and same-size rebuilds of existing structures need no setback.
• Open space and spacing: single-family lots keep 1,200 sq ft of usable open space, a detached ADU must be 15 feet from the house, and an ADU 5 feet from other accessory buildings. These can all be reduced to fit an 800 sq ft ADU.
• Historic properties: ADUs and JADUs must meet the U.S. Secretary of the Interior's standards for historic properties.

HCD's handbook says a city's maximum size rules must allow an ADU of at least 850 sq ft (1,000 sq ft with more than one bedroom), and that a minimum size can't rule out an efficiency unit, which can be as small as 150 sq ft. The city's 50% cap on attached ADUs guarantees 800 sq ft, and its minimum is 220 sq ft. Confirm with Planning how these apply to your design. [1][3][5]

Parking and garage conversions

A newly built ADU needs one parking space, which can be tandem. No parking is required if the ADU is:

• within a half-mile walk of public transit,
• in a historic district,
• part of the house or an existing accessory structure,
• where on-street parking permits are required but not offered to the ADU occupant,
• within one block of a car-share vehicle,
• a studio with no bedroom, or
• applied for together with a new house or apartment building and meets one of the cases above.

A JADU needs no parking. If you convert or tear down a garage, carport or parking space to build an ADU, you don't have to replace that parking, and the demolition permit is issued along with the ADU permit. The city's FAQ page also says ADUs "must have pedestrian access from the street." See our garage conversion guide. [1][3]

Fees

The Planning Division's fee schedule for fiscal year 2026-27 lists:

• Accessory Dwelling Unit Review: $1,940
• ADU Over-the-Counter Review: $594
• ADU Pre-Approved Plan Review: $524

Some applications also carry a 7% technology fee, and card payments carry a 2.5% processing fee. Building permit, inspection, capacity and impact fees are paid before the permit is pulled. The city says to contact each department for current amounts. School district fees are paid separately at the school district office.

Under state law, an ADU with 750 sq ft of interior livable space or less pays no impact fees, and a larger one pays in proportion to the size of the house. ADUs and JADUs under 500 sq ft don't pay school impact fees. For typical building costs see our ADU cost guide. [2][4][5][7]

How long it takes

Planning reviews an ADU first, and then the plans go to Building Safety and Public Works for plan check. With a pre-approved plan, the city says an over-the-counter submittal "may be approved in as little as one day" if it is complete and meets the code. Standard ADUs on single-family lots outside historic areas can also get an over-the-counter Planning review, according to the city's submittal checklist.

State law sets the outside limits: the city must tell you in writing within 15 business days whether your application is complete, and approve or deny a complete application within 60 days when a home already exists on the lot. See our ADU permit process guide. [4][5][8]

Junior ADUs

A JADU is up to 500 sq ft, entirely inside a new or existing single-family home or its attached garage. It needs at least an efficiency kitchen and its own exterior entrance. It can have its own bathroom or share one with the house; if it shares, it needs interior access to the house. A JADU must meet the zone's standards for the house, such as setbacks, lot coverage and height, but needs no parking. The city requires a separate address for each ADU and JADU. See our junior ADU guide.

Owner occupancy. Before the building permit is issued, the city requires a recorded covenant saying the owner will live in either the house or the JADU. The covenant also bars selling the JADU separately and limits it to its approved size. Since 2026, state law requires owner occupancy only when the JADU shares bathroom facilities with the house. Ask Planning how the covenant applies to a JADU with its own bathroom. [1][2][3][5]

Renting it out and selling

You don't have to live on the property to have an ADU. ADUs and JADUs "may not be used as a short-term vacation rental, but can be rented for periods of 30 days or more."

An ADU can be sold separately from the house only if a qualified nonprofit built the house and the ADU under state law and the applicant signs an affordable housing agreement with the city.

If you live in an HOA, the city says to check with it, but "In general, HOAs cannot prohibit the construction of an ADU or JADU." HCD's handbook says state law voids HOA rules that effectively prohibit or unreasonably restrict ADUs and JADUs on lots zoned for single-family homes. [1][2][3][5]

Pre-approved plans and financing programs

Santa Ana's Pre-Approved ADU Plans are ready-made detached ADU plan sets you can download: studios and one-bedroom units in Ranch, Spanish, Traditional, Contemporary and Craftsman styles, and a two-bedroom Contemporary plan. You still need site-specific work, including a site plan and a grading permit exemption form.

To use them, your lot must have, or be planned for, a single-family home. It can't be in a flood zone (A or AE), a historic district (French Park, the Downtown Historic District or Floral Park) or Heninger Park. Pre-approved plan applications are submitted in person on paper, by appointment.

The city's FAQ page also links two financing programs, but check their status first. CalHFA's ADU Grant Program page says "The latest round of ADU funding has been fully allocated." The Orange County Housing Finance Trust says its board voted on May 21, 2025 "to discontinue further efforts to establish the Affordable ADU Loan Program." See our ADU financing guide. [3][4][9][10][11]

Permit steps in Santa Ana

1. Check your zone

   Use the city's property information search to confirm your lot is in a zone that allows homes, and whether it's in a historic district or flood zone. [4][6]

2. Choose a standard design or a pre-approved plan

   For a custom ADU, use the ADU/JADU submittal checklist and call Planning at (714) 647-5804 for submittal instructions. For a pre-approved plan, email planning@santa-ana.org for a pre-submittal consultation. [4][8]

3. Prepare your package

   Include the signed application, dimensioned plans, the development standards compliance form and a grant deed (pre-approved plans also need a title report from the last six months). Pay the ADU Planning review fee. [4][8]

4. Submit to Planning

   Detached ADUs on single-family lots and ADU conversions can go through the city's E-Plan system with the ADU application included. Pre-approved plans are submitted over the counter on paper. [4][12]

5. Get Building Safety and Public Works approval

   After Planning approves, the plans go to Building Safety and Public Works for plan check. Call Building Safety at (714) 647-5800 and Public Works at (714) 647-5690 for their requirements. [4][8]

6. Record the JADU covenant and pay fees

   For a JADU, record the owner-occupancy covenant on the city's template. Pay permit, inspection, capacity and impact fees, and pay school fees at the school district office. [1][4][8]

7. Pull permits and schedule inspections

   Bring the city and school district clearances to pull permits, then call (714) 667-2738 to schedule inspections. [4]

Pre-approved and sample plans

• Pre-Approved ADU Plans

  Downloadable detached ADU plan sets (studio, one-bedroom and two-bedroom) for single-family lots outside flood zones and historic districts. [4][9]

Who to call

• Santa Ana Planning Division

  ADU review, submittal instructions and pre-submittal consultations (Planning@santa-ana.org)

  (714) 647-5804

  20 Civic Center Plaza, Santa Ana, CA 92701

  [4][6][8]

• Santa Ana Building Safety Division

  Building plan check requirements

  (714) 647-5800

  [8]

• Santa Ana Public Works Agency

  Public Works plan check requirements

  (714) 647-5690

  [8]

• Santa Ana building inspections

  Schedule inspections once permits are issued

  (714) 667-2738

  [4]

Questions people ask