California ADU rules · Los Angeles County
Can I Build an ADU in La Mirada?
Yes — you can build an ADU in La Mirada. California's statewide ADU law requires every city, including La Mirada, to approve a qualifying accessory dwelling unit by right, plus a junior ADU (JADU) on a single-family lot. What varies city to city are the local specifics below.
Can you build one?
ADUs allowed
CA state lawYes — by right
ADUs and JADUs are allowed by right in all residential and mixed-use zones; ministerial approval, no hearing.
Units on a single-family lot
CA state law1 ADU + 1 JADU
At least one ADU and one JADU per single-family lot (a conversion ADU may also be possible).
Units on a multifamily lot
Local ruleconversions (>=1 or 25% of units) + up to 8 detached (not to exceed number of primary units)
Detached ADUs on multifamily lots are capped at 8 or the number of existing primary units, whichever is less.
Junior ADU (JADU)
CA state lawAllowed
Up to 500 sq ft, within the walls of an existing single-family home (single-family lots only).
Size & height
Max detached ADU size
Local rule1,200 sq ft
Detached ADUs: 800 sq ft (1 bedroom or less), 1,200 sq ft (more than 1 bedroom).
Max attached ADU size
Local rule800 sq ft (1 bedroom or less), 1,200 sq ft (more than 1 bedroom), but cannot exceed 50% of primary dwelling’s floor area unless that would preclude an 800 sq ft ADU
Attached ADUs follow same size as detached, with 50% of primary dwelling cap unless it would preclude 800 sq ft.
Guaranteed minimum size
CA state law800 sq ft
An 800 sq ft ADU must be allowed regardless of FAR/lot-coverage caps; a city also cannot cap an attached ADU below 850 sq ft (1,000 for 2+ bedrooms).
Max JADU size
CA state law500 sq ft
Max height
Local rule25 ft
Standard max height is 25 ft (2 stories); up to 35 ft if above existing garage.
Setbacks
Side setback
CA state law4 ft
A city cannot require more than 4 ft side or rear setback; conversions of existing structures are exempt.
Rear setback
CA state law4 ft
Front setback
CA state lawNo front setback may block the mandatory 800 sq ft / 16-ft / 4-ft-setback ADU; otherwise per base zone
Separation from main house
Local rule6 ft
Minimum 6 ft separation between ADU and other on-site structures.
Parking
Parking required
Local ruleUp to 1 space
1 off-street space per ADU; no parking required for JADU.
Transit parking exemption
CA state lawYes — no parking required near transit & for conversions
No parking may be required within ½ mi walking distance of transit, in a historic district, for an ADU within an existing structure, within one block of car-share, or in certain permit-parking areas.
Garage-conversion replacement parking
CA state lawNot required
When a garage/carport is demolished or converted to build an ADU, replacement parking cannot be required.
Approval, timeline & cost
Approval path
CA state lawMinisterial (by right)
No public hearing or discretionary design review for a qualifying ADU.
Approval timeline
CA state law60 days
The agency must act within 60 days of a complete application — and the ADU is deemed approved if it does not.
Owner-occupancy
CA state lawOnly for a JADU
No owner-occupancy requirement for ADUs (the prior sunset was removed). A JADU may require owner-occupancy, principally where it shares sanitation with the main house.
Impact-fee waiver
CA state lawWaived under 750 sq ft
An ADU of 750 sq ft or less pays no impact fees (the 750 sq ft threshold itself is exempt under § 66311.5); larger ADUs pay fees proportional to the primary dwelling. JADUs (≤ 500 sq ft) are exempt.
Permits required
Local ruleBuilding permit, Zoning clearance
Both building permit and zoning clearance are required.
La Mirada-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Sprinkler requirements
If sprinklers are required for the main house, they are also required for the ADU/JADU.
Historic property ADUs
ADUs on historic properties must comply with all federal, state, and local historic guidelines.
La Mirada allows detached and attached ADUs up to 1,200 sq ft (if more than 1 bedroom), with a 25 ft height limit (35 ft above garages), and requires 5 ft side/rear setbacks and 6 ft separation from other structures. Multifamily lots may have up to 8 detached ADUs, not exceeding the number of primary units.
Frequently asked questions
Can I build an ADU in La Mirada?
Yes. California's statewide ADU law requires La Mirada to approve a qualifying accessory dwelling unit ministerial (by right), plus a junior ADU (JADU) on a single-family lot.
How big can an ADU be in La Mirada?
A detached ADU of at least 1,200 sq ft must be allowed, and an ADU of 800 sq ft can never be zoned out by floor-area or lot-coverage limits. A JADU can be up to 500 sq ft.
What are the setback requirements for an ADU in La Mirada?
Side and rear setbacks are limited to 4 ft. No front setback may block the mandatory 800 sq ft / 16-ft / 4-ft-setback ADU; otherwise per base zone.
Is parking required for an ADU in La Mirada?
Up to 1 space. No parking can be required within ½ mile of transit, for conversions, or for units inside the primary home. When a garage is converted, replacement parking is not required.
How long does ADU approval take in La Mirada?
A complete application must be acted on within 60 days, with ministerial (by right) — no public hearing or discretionary design review for a qualifying ADU.
Do I have to live on the property to build an ADU in La Mirada?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- La Mirada Municipal Code (LMMC) Chapter 21.54 (Accessory Dwelling Units), Ordinance 736, § 5 (part), 2025
- LMMC § 21.54.020(b)(2)(B), (C)
- LMMC § 21.54.020(b)(14)(B), (C)
- LMMC § 21.54.020(b)(14)(B)
- LMMC § 21.54.020(b)(7), (8)
- LMMC § 21.54.020(b)(8), (9)
- LMMC § 21.54.020(b)(15), (F)
- LMMC § 21.54.020(b)(5)
- LMMC § 21.54.020(b)(19)
- LMMC § 21.54.020(b)(4)
- Cal. Gov. Code §§ 66310–66342 (ADU Law)
- HCD 2025 Accessory Dwelling Unit Handbook
- Cal. Gov. Code § 66317 (ministerial approval, 60-day deadline)
- Cal. Gov. Code § 66323 (by-right ADU/JADU, 800 sq ft, 4-ft setbacks)
- Cal. Gov. Code § 66333 (junior ADUs)
- Cal. Gov. Code § 66321 (size minimums & height)
- Cal. Gov. Code § 66322 (ADU parking; § 66334 covers JADU parking)
- Cal. Gov. Code § 66314 (local ordinance standards)
- Cal. Gov. Code § 66315 (owner-occupancy)
- Cal. Gov. Code § 66311.5 (impact fees: none for an ADU ≤ 750 sq ft or JADU ≤ 500 sq ft)
Last updated 2026-06-25. This is an AI-assisted summary of La Mirada's ADU rules, drawn from its published ordinance and California ADU law — general information, not legal advice, and it may be incomplete or out of date. Verify the controlling rule for your specific parcel with La Mirada Planning before relying on it.
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