ADU rules in Los Angeles County

A detached ADU is allowed with any existing or proposed single-family home in every County zone that allows housing (R-A through R-5, the agricultural, open space, resort and watershed zones, the commercial and rural zones, and MXD), where Title 22's use tables list ADUs as SPR, Ministerial Site Plan Review; Table 22.140.640-A allows one detached ADU plus one attached or internal ADU and one JADU on a single-family lot. On multifamily lots the codified table still says two detached ADUs, but the County has applied the SB 1211 count through its November 25, 2024 memo: up to eight detached ADUs with an existing multifamily building (never more than the number of existing units) and two with a proposed one (Gov. Code 66323(a)(4)). The main local limit is fire access: on a lot in a Very High Fire Hazard Severity Zone, a locally regulated ADU needs two distinct, non-overlapping vehicular routes to a highway, each at least 24 feet wide, or direct highway frontage (22.140.640.C), but the state-exempt 800 sq ft detached unit with 4-foot side and rear setbacks (22.140.640.H.1.a.ii; Gov. Code 66323(a)(2)) is allowed regardless of access. This entry covers the unincorporated areas only, and inside the Coastal Zone the applicable Local Coastal Program governs instead of 22.140.640 (see caveats).

Attached ADUs, including additions and conversions of existing space such as garages, basements, attics and accessory structures, are allowed on the same lots: one attached or internal ADU per single-family lot alongside a detached ADU and a JADU, and on multifamily lots conversions of non-livable space (storage rooms, garages, basements and similar) for at least one unit and up to 25 percent of the existing units (Table 22.140.640-A; 22.140.640.H.1.b.i). The County defines an ADU as a unit with independent exterior access that is attached to, within, or detached from a single-family or multifamily residence (22.14.010). JADUs of up to 500 sq ft are allowed inside a single-family home, including an attached garage, and JADUs and state-exempt conversion ADUs are exempt from the fire-zone access rule (22.140.640.C, H.1.a.i, H.2). A new attached addition that is not state-exempt is subject to the same Very High Fire Hazard Severity Zone access requirement as a detached unit, and JADUs are not allowed on multifamily lots.

Section 22.140.640.G.1.a caps a locally regulated ADU at 1,200 sq ft, with no percent-of-primary limit for attached units, and sets no maximum for an ADU entirely within an existing home or converted from an existing accessory structure (plus up to 150 sq ft for ingress and egress); the minimum is 150 sq ft with one habitable room of at least 70 sq ft. Since January 1, 2026 the County measures these limits as interior livable space, per the Director's SB 543 memo of December 30, 2025. Height is 25 feet for attached or detached ADUs in the base zones; where a Community Standards District or Specific Plan sets a lower limit, at least 16 feet must still be allowed for a detached unit (18 feet, plus 2 feet for a matching roof pitch, within half a mile of a major transit stop, and 18 feet on multifamily lots), and within 200 feet of a designated scenic route or on County landmarks, historic districts and Mills Act properties a new detached ADU is held to the main home's height (and 18 feet near scenic routes), subject to the same floors. The state-exempt detached unit is capped at 800 sq ft with 4-foot side and rear setbacks, JADUs at 500 sq ft, and in the Santa Monica Mountains Coastal Zone the certified Local Implementation Program caps ADUs at 750 sq ft (22.44.1370.C.1.a).

No owner occupancy is required for an ADU: Section 22.140.640 imposes none, subsection I releases the County's interest in older covenants that required an owner to live in the home or the ADU, and Gov. Code 66315 bars owner-occupancy conditions on ADUs. JADUs are the exception, and here the codified text lags state law: 22.140.640.H.2.e.iii and H.2.f (as adopted by Ord. 2025-0029 in July 2025) require owner occupancy for every JADU and bar JADUs on corporate-owned lots, while AB 1154 limited the state requirement, effective January 1, 2026, to JADUs that share sanitation facilities with the main home (Gov. Code 66333(b)). The Director's memo of December 30, 2025 directs that a JADU covenant shall not include any owner-occupancy requirement when the JADU has its own sanitation facilities, so the operative rule is owner occupancy only for a JADU that shares a bathroom with the main home (government agencies, land trusts and housing organizations excepted), with a recorded covenant against separate sale either way. The pending Housing Ordinances Update would codify this and confine the corporate-owner bar to shared-sanitation JADUs.

Section 22.140.640.G.1.d requires no parking for an ADU outside a Very High Fire Hazard Severity Zone. Inside a VHFHSZ, Table 22.112.070 requires one uncovered standard space per ADU unless the unit has no bedroom, is within half a mile walking distance of public transit, is in a historic district, is part of the existing or proposed home or an accessory structure, sits where on-street permits are required but not offered to its occupant, is within one block of a car-share location, or is applied for together with a new home and meets one of those criteria; the space may be tandem or on a driveway. JADUs need no parking, and no replacement parking is required when a garage, carport or covered space is converted or demolished for an ADU, which the County's SB 1211 memo of November 25, 2024 extends to uncovered spaces. Separately, 22.112.070.A waives parking for uses in a public transit area, and state law caps any ADU requirement at one space per unit or per bedroom, whichever is less (Gov. Code 66314(d)(10), 66322).

Review is ministerial: every zone table lists ADUs and JADUs as SPR, Ministerial Site Plan Review under Chapter 22.186, processed as a Type I ministerial review, and where the main residential use operates under a Conditional Use Permit the ADU may instead go through a Revised Exhibit A, also a Type I review. Applicants file a DRP Base Application through EPIC-LA; the County must decide within 60 days of a complete application (22.140.640.D; Gov. Code 66317), must flag an incomplete application within 15 business days, and an incompleteness finding or denial can be appealed to the Regional Planning Commission and then the Board within a single 60-business-day window (Director's SB 543 memo of December 30, 2025). After Planning approval, Public Works Building and Safety issues the building permit, and ADU construction is exempt from a historic Certificate of Appropriateness (22.124.140.B.5). In the Coastal Zone a coastal development permit under the applicable Local Coastal Program is also needed (for a Santa Monica Mountains second unit in a fire zone or without public sewer or water, the LIP text calls for a major CDP heard by the Regional Planning Commission), though Gov. Code 66329(a) now requires a decision within 60 days and does not require a public hearing.

ADUs and JADUs may be rented, but only for terms of more than 30 consecutive days (22.140.640.F.2), and the County's short-term rental rules exclude them outright: Title 22 section 22.140.770.E.1 bars ADUs, JADUs, guesthouses and pool houses from short-term rental, and the Title 7 registration program run by the Treasurer and Tax Collector (Chapter 7.96, Ord. 2024-0015) limits short-term rentals to a registered host's primary residence and declares ADUs ineligible (7.96.050.D). An owner who lives in the ADU can still host short stays in the main home, because the host's 275-day residency may be met in an ADU (7.96.030). Neither rule reaches the Coastal Zone yet (22.140.770.B; 7.96.150.B), where the Treasurer and Tax Collector says short-term rentals are currently unregulated, although state law still requires terms over 30 days for state-exempt ADUs and JADUs (Gov. Code 66323(e), 66333(g)). An ADU cannot be sold separately from the main home except through the Gov. Code 66341 qualified-nonprofit path (22.140.640.F.1); the County has not adopted a Gov. Code 66342 condominium ordinance. ADUs with a certificate of occupancy issued after February 1, 1995 are exempt from the rent caps of the County's Rent Stabilization Ordinance (8.52.030.M).