Accessory Dwelling Units
LA County approved ADU plans
These are pre-approved standard plans — ministerial approval, no hearing or agenda item required.
What every SGV city must allow
This is the statewide floor — a city can set a more generous standard, but can't require less. Your city's actual, specific numbers are on its own city page, linked below.
| Standard | ADU | JADU |
|---|---|---|
| Max size — studio/1BR | 850 sq ft interior livable space (Gov. Code §66321(b)(2)(A)) | — |
| Max size — 2+BR | 1,000 sq ft interior livable space (§66321(b)(2)(B)) | 500 sq ft — must be within the primary residence (§66313(d)) |
| 800 sq ft protection | A city can't use FAR, lot coverage, or setback rules to block an ADU of at least 800 sq ft with 4-ft setbacks (§66321(b)(3)) | — |
| Setback (side/rear) | 4 ft — the maximum a city may require (§66321(b)(3)) | No numeric setback; must be safe for fire access on conversion |
| Height — detached | 16 ft floor (18 ft near transit or on a multifamily lot) (§66321(b)(4)) | N/A |
| Height — attached | 25 ft, or the primary dwelling's own limit, whichever is lower | N/A |
| Owner-occupancy | Prohibited — a city can't require it (§66315) | Required only if the JADU shares a bathroom with the main house (§66333(b)) |
| Fee | Exempt under | Statute |
|---|---|---|
| Impact fees (Mitigation Fee Act + Quimby) | 750 sq ft — charged proportionately above it | Gov. Code §66324(c)(1) |
| School developer fees | 500 sq ft interior livable space | Ed. Code §17620 / Gov. Code §66311.5 |
The gap: the 800 sq ft size protection above and the 750 sq ft fee exemption come from two different bills and don't line up. An ADU built at the maximum protected size can still trigger impact fees a smaller unit wouldn't.
- Parking — no space can be required if the ADU is within ½ mile of transit, in a historic district, replacing demolished parking, part of the primary residence, or built alongside a new primary dwelling on the same lot.
- Fire sprinklers — an ADU never triggers a sprinkler requirement the primary residence doesn't already have.
- Unit count — every single-family lot gets one ADU plus one JADU as-of-right, regardless of local zoning density limits.
LA County pre-approved plans
- 1,200 sq ft
ADU Plan A
LA County pre-approved standard ADU plan, 1,200 sq ft.
View plan (PDF) - 1,200 sq ft
ADU Plan B
LA County pre-approved standard ADU plan, 1,200 sq ft, alternate layout.
View plan (PDF) - 800 sq ft
ADU Plan C
LA County pre-approved standard ADU plan, 800 sq ft.
View plan (PDF) YOU ADU Standard Plan
LA County pre-approved standard ADU plan.
View plan (PDF)
Your city's specific numbers
- Arcadia
- Altadena
- La Cañada Flintridge
- Pasadena
- San Marino
- South Pasadena
- Sierra Madre
- Alhambra
- Montebello
- Monterey Park
- Rosemead
- San Gabriel
- Temple City
- Azusa
- Duarte
- Glendora
- Monrovia
- Diamond Bar
- Hacienda Heights
- Rowland Heights
- Walnut
- Claremont
- La Verne
- Pomona
- San Dimas
- Baldwin Park
- Covina
- El Monte
- La Puente
- South El Monte
- West Covina
- Irwindale
- City of Industry
How ADU law got here
| Bill | Effective | What changed |
|---|---|---|
| SB 1069 / AB 2299 | 2017-01-01 | Renamed "second units" to ADUs; required ministerial approval standards. |
| AB 68 / SB 13 | 2020-01-01 | 60-day ministerial clock; no minimum lot size blocking 800 sq ft units; impact fees prohibited under 750 sq ft. |
| AB 434 / AB 1033 | 2024-01-01 | HCD/local enforcement of State ADU Law; opt-in condo sale of an ADU. |
| AB 976 | 2025-01-01 | Owner-occupancy requirement permanently eliminated for ADUs. |
| SB 1211 | 2025-01-01 | Multifamily detached ADU allowance expanded to up to 8 units. |
| SB 543 | 2026-01-01 | 60-day clock now deemed-approved if missed; 15-business-day completeness review. |
This is not legal advice, and it is not exhaustive — always confirm current requirements with your city's planning department or a licensed California real estate attorney before relying on any figure here. See our Insights coverage for more detail.
The plans above are LA County's own pre-approved set — they are not the only ones available. Several individual SGV cities publish their own pre-approved plan libraries (some free, some at a cost), separate from the County's. Before using any pre-approved plan, confirm it still matches your city's current building code — cities update their ordinances, and a plan approved under an older standard is not guaranteed to still qualify.