Building an ADU in Irvine

Which rules apply in Irvine

Irvine's ADU ordinance, No. 18-05, dates from April 2018. The city's ADU page says Irvine "is reviewing Accessory Dwelling Unit (ADU) and Junior Accessory Dwelling Unit (JADU) applications per state statute."

The California Department of Housing and Community Development (HCD) reviewed the old ordinance and, in a January 2025 findings letter, listed 14 ways it fails to comply with state law. Among them: a 5,000 sq ft minimum lot size, a one-story, 15.5-foot height cap for detached ADUs, side and rear setbacks over 4 feet, a 120-day review period, owner-occupancy and deed restriction requirements, and replacement parking for converted garages.

In February 2025 the city wrote to HCD that it has not enforced the ordinance since January 1, 2020, that the ordinance "is null and void and is superseded by State Law," and that it intends to apply state law instead. The city says it applies state law instead, so the state standards on our California page are the ones to plan around. Because the ordinance is still on the books, confirm any specific number with the Planning Team at 949-724-6308 before you design. [1][2][4]

What HCD told Irvine in 2025

In a March 27, 2025 letter, HCD said the city "has misapplied State ADU Law in the processing of ADU applications by requiring deed restrictions and disallowing JADUs in townhomes." HCD's points:

• Deed restrictions. HCD had received a complaint that the city would not accept an ADU application without a deed restriction barring separate sale of the ADU. HCD's position is that a deed restriction is an "additional standard" that state law does not allow for an ADU, and that it can't be the reason to call an application incomplete.
• Junior ADUs in detached townhomes. HCD said "a detached townhouse on its own lot is a single-family primary dwelling and would therefore be eligible for a JADU." HCD's handbook adds that a JADU is also allowed in each half of a "half-plex" (two homes on separate lots sharing a wall), but not in a duplex on one lot.
• The ordinance itself. HCD said the city had neither amended the ordinance nor adopted findings defending it, as state law requires, and urged the city to repeal it.

The city's ADU page still lists a notarized, recorded covenant among the submittal items. If a covenant is requested for your ADU, ask the Planning Team what it contains, and see HCD's ADU Handbook, which says a city "cannot impose a deed restriction on an ADU" (a JADU deed restriction limited to no separate sale and the JADU's size is allowed). HCD takes complaints about local ADU decisions; see "If your city says no" on our California page. [1][2][3]

Size, height and setbacks

With no compliant local ordinance, the state's default limits apply. Sizes are measured as interior livable space.

• Detached ADU: up to 1,200 sq ft.
• Attached ADU: up to 50% of the existing home's floor area, but rules can't stop an ADU of at least 800 sq ft with 4-foot side and rear setbacks.
• Conversions: an ADU inside existing space of the house or an accessory structure such as a garage. A conversion of an accessory structure can add up to 150 sq ft for getting in and out.
• Height: a detached ADU can be at least 16 feet, or 18 feet within a half-mile of a major transit stop or high-quality transit corridor (plus 2 feet to match the house's roof pitch). An attached ADU can be 25 feet or the zone's height limit for the house, whichever is lower. HCD also told Irvine that an ADU may sit entirely on the second story of an attached accessory structure such as a garage.
• Setbacks: no more than 4 feet from side and rear lot lines for a new ADU, and none when you convert an existing structure or rebuild one in the same place and size.
• Lot size: no minimum lot size can be required.

Irvine's old ordinance had a 5,000 sq ft minimum lot, size caps by lot size, and design rules such as matching roof color and "harmony with the neighborhood." HCD found these don't comply with state law. [3][4]

Parking

State law caps ADU parking at one space per ADU or per bedroom, whichever is less, and the space can be tandem on a driveway. No parking can be 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 permits are required but not offered to the ADU occupant, within one block of a car-share vehicle, or applied for together with a new home on the lot (if one of the other cases also applies).

If you tear down or convert a garage, carport or parking space to build an ADU, the city can't make you replace that parking. HCD flagged Irvine's old rule requiring replacement spaces as unlawful. [3][4]

Fees

City fees. Irvine's fee schedule (effective August 15, 2026) lists an "Accessory Dwelling Unit" code compliance case: $217.64 per hour, with a $1,500 initial deposit and a $300 minimum balance. Building plan check fees are paid when plans are submitted, and permit fees when the permit is issued; the city says permit fees are "based on the cost per square foot and the type of construction." See the city's fee schedule page or call the Permit Processing Counter at (949) 724-6313.

School fees. Four school districts serve Irvine, and all charge fees on new residential space. The city's School Facilities Fee Determination form has an exemption box for an "ADU is 749 sq. ft. or less," and the city's info sheet says residential projects under 500 sq ft are exempt. Under state law, ADUs and JADUs under 500 sq ft of interior livable space aren't subject to school impact fees. Because these differ, confirm with your school district which exemption applies to your ADU. Areas inside certain Community Facilities Districts don't pay Irvine Unified fees, but you still need a Certificate of Compliance from the district before the permit is issued.

Other forms with costs. The application package includes a Transportation Corridor Agencies (TCA) fee determination. ADU projects must also submit an online construction and demolition waste management plan, approved before the permit is issued, and the city's waste assessment form says covered projects post a bond at permit issuance.

Impact fees. Under state law, an ADU with 750 sq ft of interior livable space or less pays no impact fees, and a larger one pays a share in proportion to the size of the house. For typical costs see our ADU cost guide. [3][5][6][7][8]

How long it takes

After you submit on IrvineReady!, the city says staff will check your package for completeness "within approximately two business days." You then get an emailed link to pay fees, and review starts only after payment.

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. If it denies, it must give you a full list of the problems and how to fix them within the same 60 days. HCD's 2025 findings told Irvine its old 120-day review period was too long. More in our ADU permit process guide. [1][3][4][8]

HOAs, garage conversions and junior ADUs

HOAs. Much of Irvine is in homeowners associations, and the city's application package warns that "Your Homeowners Association may have its own approval process." State law voids CC&Rs that prohibit or unreasonably restrict ADUs or JADUs on single-family lots. An HOA may set limited, reasonable objective design standards, but it can't charge fees as a condition or delay review beyond 60 days, and it can't influence the city's approval. If an HOA blocks you, HCD suggests contacting the city and getting legal advice.

Garage conversions. Converting an attached or detached garage needs no setbacks beyond what the existing structure has, and you don't have to replace the lost parking. A converted accessory structure can add up to 150 sq ft for entry and exit. See our garage conversion guide.

Junior ADUs. A JADU is up to 500 sq ft, entirely inside a single-family home, which can include an attached garage (not a detached building). It needs at least an efficiency kitchen, and if it has no bathroom of its own it needs an interior door to the house. You must live on the property only if the JADU shares a bathroom. See our junior ADU guide. [2][3][8]

Renting it out

State law doesn't let a city require you to live on the property to have an ADU. ADUs approved under the state's mandatory categories, and all JADUs, must be rented for terms longer than 30 days, and a city may require the same of other ADUs.

Irvine's zoning rules on boarding houses also matter. The city's boarding house page says a boarding house is a residence "where there are two or more rental agreements," and that these are prohibited in many locations. In a 2025 email quoted by HCD, city staff said Irvine's zoning code treats housing for less than 31 consecutive days as a boarding house. Ask Planning at 949-724-6308 how these rules apply before you rent.

Selling an ADU separately is allowed in California only where a city adopts a condo ordinance or through a qualified nonprofit; the city told an applicant in 2025 that it has not adopted such an ordinance. [2][3][9]

Permit steps in Irvine

1. Get an ADU Verification Form from Planning

   Email planning@cityofirvine.org or call 949-724-6308. Planning staff must complete and sign the ADU Verification Form, which confirms your property is eligible. [1][8]

2. Check with your HOA

   The city's package notes your HOA may have its own approval process. Under state law, HOA rules can't block or unreasonably restrict an ADU. [3][8]

3. Prepare the application package

   Download the ADU permit application package. It includes the building permit application, residential take-off sheet, construction waste assessment, OCFA plan submittal criteria, developer deposit form, TCA and school fee determinations and an address application. You also need plans, calculations and a City Standard Title Sheet. [1][8]

4. Submit on IrvineReady!

   Upload everything through the IrvineReady! portal, choosing "For Permitting--Other" as the project type. The city recommends Google Chrome. [1]

5. Pay fees and go through review

   Staff check completeness in about two business days and email you a link to pay plan review fees. Review begins after payment. OCFA may need to review the plans, for example if the house has fire sprinklers. [1][8]

6. Pay school and other fees, then get the permit

   If school fees apply, pay the school district and bring its Certificate of Compliance to the city. If your project is covered by the construction waste rules, post the bond; pay permit fees at issuance. [6][7][8]

7. Build and pass inspections

   Schedule inspections through Building and Safety; the inspection information line is 949-724-6501. [8]

Who to call

• City of Irvine Planning Team

  ADU eligibility, ADU Verification Form and zoning questions (planning@cityofirvine.org)

  949-724-6308

  1 Civic Center Plaza, Irvine, CA 92606

  [1]

• City of Irvine Permit Processing Counter

  Plan check and permit fees

  (949) 724-6313

  [6]

• City of Irvine Building and Safety

  Permit information (949-724-6300) and inspections

  949-724-6501

  [8]

Questions people ask