Building an ADU in Huntington Beach

Which rules apply in Huntington Beach

The city's ADU page says that Section 230.10 of the Huntington Beach Zoning and Subdivision Ordinance "previously regulated Accessory Dwelling Units," but that after new state ADU and junior ADU laws took effect on January 1, 2020, "the HBZSO Section 230.10 is no longer in effect." The section is still printed in the online zoning code, where it calls for "director approval," so don't rely on its older limits.

The city says it "provides ministerial review for all JADUs and ADUs," refers applicants to the California Department of Housing and Community Development's ADU Handbook, and mentions a city ADU handout with development standards. Ask the Permit Center at (714) 536-5271 for a copy.

The statewide standards are summarized below and on our California page. Confirm the details for your lot with the city before you design. [1][2][3]

Huntington Beach and the state: what official sources say

ADU processing in 2023. In February 2023, the City Council considered directing staff to stop processing ADU applications and permits under state law "until the courts have adjudicated the matter(s)." The state housing agency (HCD) sent the city a notice of potential violation saying that refusing to process ADU permits "would be unlawful and in violation of state law." The city's ADU page now says: "Per City Council's direction at the March 7, 2023 City Council meeting, City staff will continue accepting Accessory Dwelling Unit (ADU) applications."

The housing element lawsuit. Separately, on March 9, 2023, the state sued the city for failing to adopt a compliant housing element on time (its state-required housing plan). According to the California Attorney General:

• On December 19, 2025, the San Diego Superior Court ordered the city, among other things, to adopt a housing element within 120 days, and restricted its land use authority, effective immediately, until it does.
• On May 15, 2026, the court imposed civil penalties of $160,000, then $50,000 a month starting June 2026, until the city cures the violation. The city's federal lawsuit challenging state housing laws was dismissed, and the U.S. Supreme Court denied the city's request to review those rulings.
• On July 1, 2026, the court struck the city's cross-complaint against the state and ruled that the state may seek its attorney's fees. The court set a July 17 hearing on additional issues, including penalties and a pending affordable housing application.

These releases concern the city's housing element. If your ADU permit is delayed, HCD takes complaints about local ADU decisions (see our California page). [1][4][5][6][7]

Size, height and setbacks

Where a city has no compliant ADU ordinance, state law sets the limits. 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 at least 800 sq ft must be allowed.
• Conversions: one ADU inside existing space of the house or an accessory structure such as a garage; converting an accessory structure can add up to 150 sq ft for getting in and out.
• Height: at least 16 feet for a detached ADU, 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).
• Setbacks: no more than 4 feet from side and rear lot lines for a new ADU, and none for a conversion or a rebuild in the same place and size.
• Lot size: no minimum lot size can be required, and lot coverage or floor area limits can't block an 800 sq ft ADU with 4-foot side and rear setbacks.

On a single-family lot, HCD says state law allows one converted ADU, one new detached ADU and one junior ADU together. Lots with apartment buildings can add ADUs in non-living space and detached ADUs. Your HOA can't prohibit an ADU; state law voids CC&Rs that do. [2]

Coastal Zone

The city's ADU page says that "development in the Coastal Zone may require Coastal Development Permits." Check with the Permit Center whether your lot is in the Coastal Zone.

Under state law, when a certified local coastal program covers ADUs, the city must approve or deny a coastal development permit for an ADU within 60 days of a complete application (when a home already exists) and doesn't have to hold a public hearing; the coastal review runs at the same time as the ADU review. The city's 2026-27 planning fee schedule lists Coastal Development Permit fees, including $5,929 for a single-family dwelling at the Zoning Administrator level and $564 for a coastal categorical exclusion letter; ask which, if any, applies to your ADU. [1][2][8]

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 with a new home on the lot (if another exemption also applies).

If you tear down or convert a garage, carport or parking space to build an ADU, the city can't require you to replace that parking. [2]

Fees

Impact fees. Huntington Beach's development impact fee table, updated July 1, 2026, lists a separate rate per ADU: $183.50 law enforcement, $86.00 fire, $341.00 circulation (streets), $213.00 library and $3,130.00 parks, or $3,953.50 in total. A new single-family home pays far more. State law says an ADU with 750 sq ft of interior livable space or less pays no impact fees, and a larger one pays only a share in proportion to the size of the house, so ask the city how these rates apply to your ADU.

Planning fees. The 2026 planning fee schedule adds a 6% automation fee to all fees. It still lists "Accessory Dwelling Units" under an Administrative Permit fee of $2,764. The city says ADU review is ministerial, so ask whether any planning fee applies.

Building fees. Building permit fees are based on project valuation. The city has a Building Permit Fee Calculator for estimates; it covers the building permit only, not plumbing, mechanical, electrical or other departments' fees. Card payments carry a 3% service fee.

Under state law, ADUs and JADUs under 500 sq ft of interior livable space are not subject to school impact fees. More in our ADU cost guide. [2][8][9][10]

Pre-approved ADU plan

Under AB 1332, the city offers the free HB Pre-Approved ADU Plan: a one-story, detached, 490 sq ft ADU with one bedroom and one bathroom. It comes in three architectural styles (California Ranch, Bungalow and Spanish Colonial), and the city says using it saves design time and money and gets a streamlined review. Modifications or deviations from the plan are not allowed.

The plan set itself (dated February 25, 2026) says it can't be used if the ADU would be 4 feet or less from any property line, or less than 8 feet 6 inches from any other building or structure. Download the brochure and full plan set from the city's ADU page. For other options, see our prefab ADU guide. [1][11][12]

Garage conversions and junior ADUs

Garage conversions. Under state law, converting an existing garage or other accessory structure needs no new setbacks, can add up to 150 sq ft for entry and exit, and you don't have to replace the lost parking. See our garage conversion guide.

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

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 more than 30 days.

Huntington Beach's short-term rental ordinance (Chapter 5.120) allows short-term rentals (30 nights or fewer) with a permit, generally in owner-occupied homes. It says ADUs or JADUs "may be permitted as a STR only if the unit was legally established prior to the effective date of this ordinance" (adopted in 2021). A new ADU therefore can't become a short-term rental. The permit costs $658 under the 2026 planning fee schedule. [2][8][13]

Permit steps in Huntington Beach

1. Check your zoning and Coastal Zone status

   Call the Permit Center at (714) 536-5271 for your property's zoning and whether a Coastal Development Permit may be needed. Ask for the city's ADU handout. [1][14]

2. Choose a design

   Hire a designer, or use the free HB Pre-Approved ADU Plan if your site meets its setback and separation limits. [1][12]

3. Request an address

   For a new ADU, submit an address assignment application through the city's Accela Citizen Access portal under Planning (not under the building permit documents). [12]

4. Apply for plan check and permits online

   Apply for the building permit and plan check through the same portal, where you can also check your project's status. [1][10]

5. Get a Coastal Development Permit if required

   In the Coastal Zone, the coastal permit is processed at the same time as the ADU review, and state law requires a decision within 60 days of a complete application where the local coastal program covers ADUs. [1][2]

6. Pay fees, get the permit and build

   Pay impact, planning and building fees as assessed, then schedule inspections. Official city emails come only from @surfcity-hb.org addresses; the city warns of phishing scams asking applicants for payment. [8][10]

Pre-approved and sample plans

• HB Pre-Approved ADU Plan

  Free plan for a one-story, detached 490 sq ft ADU (1 bedroom, 1 bath) in California Ranch, Bungalow or Spanish Colonial style; no modifications allowed. [1][11]

Who to call

• City of Huntington Beach Permit Center

  Zoning information, ADU permits and plan check (permitcenter@surfcity-hb.org)

  714-536-5271

  2000 Main Street, Huntington Beach, CA 92648

  [10][11]

Questions people ask