A State ADU is capped at 800 square feet but needs no parking and carries the strongest protections. An Ordinance ADU, under LA's own code, can reach 1,200 square feet detached, but it needs a parking space unless an exemption applies and it carries more local conditions.
Los Angeles administers its ADU ordinance, LAMC 12.22 A.33, together with state ADU law through a Zoning Administrator memo. In practice that gives homeowners a choice of route, and the right one depends on the lot, the street, and what you want to build.
Side by side
| State ADU | LA Ordinance ADU | |
|---|---|---|
| Size | Up to 800 sq ft for a new detached unit | Detached up to 1,200 sq ft, unless zoning caps it lower; attached up to 50% of the house |
| Height | 16 ft detached (more near transit); LA allows 2 ft more for a matching roof pitch, up to 20 ft | Detached: the zone's height limit; attached: 25 ft or the zone limit |
| Setbacks | 4 ft side and rear | 4 ft side and rear |
| Parking | None required | 1 space unless a state exemption applies |
| Hillside and Very High fire zone limits | Not applied | Street dedication for 20 ft frontage may still apply |
The State ADU route
The state route is built on the guarantee in Government Code 66321: a city cannot use size, lot coverage, or floor area limits to block an ADU of at least 800 square feet with 4 foot side and rear setbacks. In Los Angeles, the State ADU needs no parking, and local caps below 800 square feet, such as some historic district limits, do not apply to it.
The Ordinance ADU route
The city route allows a larger unit. A detached Ordinance ADU can reach 1,200 square feet and the zone's height limit, which suits a one bedroom with real living space or a two or three bedroom unit. In exchange, it needs one parking space unless a state exemption applies, and on hillside lots in a Very High Fire Hazard Severity Zone the city may still require a street dedication to reach a 20 foot frontage.
LA's ADU ordinance is being updated as part of the city's Missing Middle housing package, which was in public hearings in October 2026. We check its status before every design.
Hillside, historic, and coastal lots
Hillside and fire zones: LA's ordinance restricts ADUs on lots that are both in a Hillside Area and a Very High Fire Hazard Severity Zone. The city does not apply that restriction to State ADUs, and drops its sprinkler and parking parts for Ordinance ADUs where they conflict with state law.
Historic districts (HPOZs): no ADU parking is required, and HPOZ size caps under 800 square feet do not apply to a State ADU.
Coastal Zone: either route still needs a Coastal Development Permit. State law requires a decision within 60 days.
How to choose
If 800 square feet works and parking is tight, the State ADU is usually the simpler path. If you want more space and the lot can take a parking space, the Ordinance ADU opens up a bigger unit. Fees also matter: a unit of 750 square feet or less pays no impact fees. Start with ADU rules in Los Angeles for the full set of limits.
Look up your address on ZIMAS, the City of Los Angeles's free online parcel map. It shows your lot's zone and height district, and whether it sits in a specific plan, a historic district (HPOZ), or another overlay. Those details decide which of the rules above apply to your property.
Common questions
What is the difference between a State ADU and an Ordinance ADU in LA?
A State ADU follows state law: up to 800 square feet, no parking, and the strongest protections. An Ordinance ADU follows LAMC 12.22 A.33: up to 1,200 square feet detached, but with a parking space unless exempt and more local conditions.
Can I build a 1,200 square foot ADU in Los Angeles?
Under the Ordinance ADU route, a detached ADU can reach 1,200 square feet, unless floor area, lot coverage, or other zoning limits cap it lower on your lot.
Does an ADU on a hillside lot in LA need parking?
A State ADU does not. For an Ordinance ADU, the city does not apply its hillside parking and sprinkler conditions where they conflict with state law, but a street dedication may still be required.
LA City Planning ZA Memo 143, Rev. 1 | HCD findings letter to LA (Nov 2024) | Gov. Code 66321 | Missing Middle LA hearing
Rules change and every lot is different. This guide is general information, not advice for your property; confirm the rules for your lot before you design or build.