California ADU rules · Los Angeles County
Can I Build an ADU in Monterey Park?
Yes — you can build an ADU in Monterey Park. California's statewide ADU law requires every city, including Monterey Park, 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
Local rule1 detached ADU (new, up to 800 sqft, 4' setbacks) + 1 JADU (within existing/proposed SFR, up to 500 sqft) + 1 ADU converted from existing space (e.g., garage conversion); all three may be allowed if site conditions permit
Allows up to 3 units (1 detached ADU, 1 JADU, 1 conversion ADU) on a single-family lot if site conditions allow.
Units on a multifamily lot
Local ruleConversions: at least 1 ADU or up to 25% of existing units from non-livable space; up to 2 detached ADUs (new) on lot with proposed multifamily; up to 8 detached ADUs (new) on lot with existing multifamily, not to exceed number of existing units
Detached ADU cap on existing multifamily lots is the lesser of 8 or the number of existing units.
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
CA state law1,200 sq ft
Statewide default cap for detached new-construction ADUs in the absence of a compliant local ADU ordinance. The unconditional by-right floor a city must always allow is 800 sq ft (see Guaranteed minimum size); a city with a compliant ordinance may set its own ceiling.
Max attached ADU size
Local rule50% of primary, >=850 (>=1,000 for 2+ bedrooms)
Explicitly follows state attached ADU size rule.
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 rule16 ft
16 ft base for detached; up to 18 ft near transit/multistory; attached ADUs up to 25 ft or primary dwelling height.
Setbacks
Side setback
Local rule4 ft
4 ft minimum for new detached ADUs.
Rear setback
Local rule4 ft
4 ft minimum for new detached ADUs.
Front setback
Local ruleNo minimum front setback may preclude an 800 sqft ADU with 4' side/rear setbacks; ADU may be allowed in front setback if no other location is feasible
Front setback cannot block a compliant ADU; ADU may be in front setback if needed.
Separation from main house
CA state lawNone required
No statewide separation requirement between the ADU and the primary dwelling.
Parking
Parking required
Local ruleUp to 1 space
Max 1 space per ADU or per bedroom; multiple state exemptions apply.
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, Planning permit, Utility permit, Demolition permit (if garage conversion)
Demolition permit for garage conversion must be processed concurrently.
Monterey Park-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Fire code compliance
ADUs must comply with local fire/building codes; fire sprinklers not required unless for primary dwelling.
Historic district
Additional notice/placard may be required for garage demolition in historic districts.
Monterey Park allows up to three units (detached ADU, JADU, and conversion ADU) on a single-family lot if site conditions allow, and requires additional notice for garage conversions in historic districts. The city must develop a pre-approved ADU plan program by 2025.
Frequently asked questions
Can I build an ADU in Monterey Park?
Yes. California's statewide ADU law requires Monterey Park 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 Monterey Park?
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 Monterey Park?
Side and rear setbacks are limited to 4 ft. No minimum front setback may preclude an 800 sqft ADU with 4' side/rear setbacks; ADU may be allowed in front setback if no other location is feasible.
Is parking required for an ADU in Monterey Park?
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 Monterey Park?
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 Monterey Park?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Monterey Park Zoning Code, Chapter 21.50 (ADUs/JADUs); Ordinance 2261, April 16, 2025
- Monterey Park Zoning Code, Ch. 21.50; Gov. Code § 66323
- Monterey Park Zoning Code, Ch. 21.50; Gov. Code § 66321(b)(2)
- Monterey Park Zoning Code, Ch. 21.50; Gov. Code § 66321(b)(4)
- Monterey Park Zoning Code, Ch. 21.50; Gov. Code § 66321(b)(3), § 66323(a)(2)
- Monterey Park Zoning Code, Ch. 21.50; Gov. Code § 66322(a), § 66314(d)(10)
- Monterey Park Zoning Code, § 21.50.040
- Monterey Park Zoning Code, Ch. 21.50; Gov. Code § 66314(e)-(f)
- Monterey Park Zoning Code, Ch. 21.50
- 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 § 66333 (junior ADUs)
- Cal. Gov. Code § 66321 (size minimums & height)
- Cal. Gov. Code § 66323 (by-right ADU/JADU, 800 sq ft, 4-ft setbacks)
- 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 Monterey Park'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 Monterey Park Planning before relying on it.
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