ADU rules in Huntington Beach

Detached ADUs are allowed ministerially under state standards, which Huntington Beach applies because it has no operative local ADU ordinance: its ADU page says HBZSO Section 230.10 'is no longer in effect' and that the city 'provides ministerial review for all JADUs and ADUs'. Gov. Code 66314(d)(3) allows a unit detached from the home on the same lot, and 66323(a)(2) and (a)(4) require approval of a new detached unit on a single-family lot and, beside an existing multifamily building, up to eight detached units not exceeding the number of existing units (two with a proposed multifamily building). The codified 230.10 still demands that the unit be attached to the main dwelling, a 6,000 sq ft lot and a lot with a single-family home, but Gov. Code 66316 makes a noncompliant ordinance null and void and the city does not apply it. The city's own free pre-approved plan is a one-story, 490 sq ft detached ADU. Coastal-zone lots also need a coastal development permit, which the Planning Commission denied for two detached state-exempt units on 9-8-2026 (see permitType).

Attached additions and conversions of space inside the home, an attached garage or an existing accessory structure are allowed (Gov. Code 66314(d)(3)); one ADU converted from existing space (with up to 150 sq ft of expansion of an accessory structure for access) plus one JADU per single-family lot must be approved ministerially (66323(a)(1)). JADUs of up to 500 sq ft of interior livable space inside a single-family home are allowed (66313(d)), and on multifamily lots conversions of non-livable space such as storage rooms, garages, attics and basements must be allowed for at least one unit and up to 25 percent of the existing units (66323(a)(3)). The codified 230.10.A still conditions any ADU on Director approval with findings that it 'maintains the scale of adjoining residences' and matches the house's materials, and 203.06 still defines an accessory unit as one 'in the RL zone', but the city treats 230.10 as no longer in effect and reviews ADUs ministerially. In the coastal zone an attached or internal unit may also need a coastal development permit.

With 230.10 inoperative, the state standards govern: an attached ADU may not exceed 50 percent of the existing primary dwelling and a detached ADU 1,200 sq ft (Gov. Code 66314(d)(4)-(5)), but no percentage, lot coverage, floor area ratio or open space rule may prevent an ADU of at least 800 sq ft of interior livable space with 4-foot side and rear setbacks (66321(b)(3)); the city's withdrawn October 2023 summary also read the 850 sq ft (one bedroom) and 1,000 sq ft (more than one bedroom) figures of 66321(b)(2) into the attached limit. The state-exempt new detached unit may be held to 800 sq ft of livable space and 16 feet in height (18 feet within half a mile of a major transit stop or high-quality transit corridor, plus 2 feet for a matching roof pitch, or on a lot with a multistory multifamily building), while conversions of existing space have no size cap beyond a 150 sq ft access expansion of an accessory structure (66323(a)(1)-(2), 66321(b)(4)). JADUs are capped at 500 sq ft of interior livable space (66313(d)). The codified 230.10.B.1-2 still prints a 650 sq ft, one-bedroom cap on a 6,000 sq ft minimum lot, which state law voids (66316; 66314(b)(1) bars minimum lot sizes). The 2023 summary applied base-zone height, setback and lot coverage standards to units larger or taller than the state-exempt unit, and an attached unit may reach 25 feet or the zone's height limit, whichever is lower (66321(b)(4)(D)).

No owner-occupancy requirement applies to ADUs: Gov. Code 66315 bars any standard beyond 66314, 'including an owner-occupant requirement'. The codified 230.10.A.3 still makes owner occupancy of the main dwelling or the ADU an approval condition and 230.10.D requires a recorded ownership covenant, but the city treats the section as no longer in effect and 66316 voids it; the city's withdrawn 2023 summary also described the exemption as covering only units built between January 1, 2020 and January 1, 2025, a sunset that current 66315 does not contain. For JADUs the owner must live in the house or the JADU only when the JADU shares sanitation facilities with the main home (66333(b), as amended by AB 1154 effective January 1, 2026), and a deed restriction barring separate sale and fixing the JADU's size and attributes is recorded (66333(c)); the 2023 summary still printed an unqualified 'Owner shall live in either unit' for JADUs. Owner presence matters separately for short-term rental: outside Sunset Beach a grandfathered ADU can be an STR only as a hosted stay with the owner on site (HBMC 5.120.020, 5.120.040.C).

HBZSO 231.18.D.11 (last amended by Ord. 4196, March 2020) requires 'One additional off-street parking space' for an accessory dwelling, 'except that in the coastal zone there shall be a minimum of four parking spaces on-site'. Under state law, which applies 'whether or not the local agency has adopted an ordinance' (Gov. Code 66322), parking may not exceed one space per ADU or per bedroom, whichever is less, and may be tandem on a driveway (66314(d)(10)); none may be required within one-half mile walking distance of public transit (a bus stop counts, 66313(m)), in an architecturally and historically significant historic district, for a unit inside the home or an accessory structure, where on-street permits are required but not offered, within one block of a car-share vehicle, or for an ADU permitted with a new home (66322(a)); spaces lost when a garage or carport is converted or demolished need no replacement (66314(d)(11)); and state-exempt 66323 units take no parking standard (66323(b)). Staff's 9-8-2026 Planning Commission report applied the transit exemption to two coastal-zone 66323 units, but commissioners cited coastal parking when they denied that permit, the city's withdrawn 2023 summary said 'Minimum parking standards apply in the Coastal Zone' for garage conversions, and the Coastal Commission's April 21, 2020 memo says certified LCP ADU provisions keep applying to coastal permits until an LCP amendment. Outside the exemptions, coastal-zone lots may therefore be asked for more than one space; confirm with the Planning Division before designing around a parking count.

Outside the coastal zone ADUs and JADUs get ministerial building-permit review with no hearing: the city says it 'provides ministerial review for all JADUs and ADUs', and Gov. Code 66317(a) requires a completeness determination within 15 business days and approval or denial within 60 days of a complete application, failing which the application is deemed approved. Inside the coastal zone (CZ overlay, HBZSO Chapter 221) the city page warns that ADUs 'may require Coastal Development Permits', and the certified LCP requires a public hearing before any CDP action (245.18), taken by the Zoning Administrator when no other discretionary approval is involved (245.16) and appealable to the Planning Commission and the City Council (245.32). Gov. Code 66329(a) requires a CDP decision on an ADU within 60 days and says no hearing is required, yet the city still holds one, and on 9-8-2026 the Planning Commission voted 4-2 on a council member's appeal to deny CDP No. 26-006 for two state-exempt detached ADUs at 205 Pecan Avenue that staff and the Zoning Administrator had approved under 66323. In the uncertified Sunset Beach specific plan area (SP17) the city's Sunset Beach Local Coastal Program Review Board grants an 'Approval in Concept' and the Coastal Commission issues the coastal permit.

An ADU may be rented separately from the main home but not sold or conveyed separately (Gov. Code 66314(d)(1), apart from the 66341 qualified-nonprofit path), and Huntington Beach has adopted no Gov. Code 66342 ADU-condominium ordinance, as the 9-8-2026 Planning Commission staff report confirms. Rentals of state-exempt 66323 units and of JADUs must be for terms longer than 30 days (66323(e), 66333(g)). HBMC Chapter 5.120 (Ord. 4224, adopted 1-19-2021, amended by Ord. 4238, adopted 11-2-2021) requires a city permit for any rental of 30 or fewer consecutive nights and allows an ADU or JADU as an STR 'only if the unit was legally established prior to the effective date of this ordinance' (5.120.030.F.8), a date the city's STR page gives as February 19, 2021. Qualifying units must be hosted stays with the owner on site anywhere outside Sunset Beach (Zone 1), unhosted STRs survive only in Sunset Beach (Zone 2) for operators permitted by March 1, 2022, and the chapter limits each host and each property to one permit (three for ownership complexes of four or more units), sets a 25-year minimum guest age and collects the 10 percent transient occupancy tax plus the 6 percent TBID assessment.