California ADU rules · Los Angeles County
Can I Build an ADU in Avalon?
Yes — you can build an ADU in Avalon. California's statewide ADU law requires every city, including Avalon, 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 2 (proposed multifamily) or up to 8 detached (existing multifamily), not to exceed number of existing units
Avalon limits detached ADUs on multifamily lots to 2 for proposed multifamily and up to 8 for existing multifamily, but never more than 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
Local rule1,000 sq ft
Detached ADUs: 850 sqft (studio/1-bed), 1,000 sqft (2+ beds); never less than 800 sqft if other standards would reduce it.
Max attached ADU size
Local rule850 (studio/1-bed), 1,000 (2+ beds), AND no more than 50% of primary dwelling; must allow at least 800 sqft
Attached ADUs are capped at 850/1,000 sqft and 50% of primary, but must allow at least 800 sqft.
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
CA state law16 ft
16 ft baseline; cities must allow 18 ft within ½ mi of a major transit stop or where the primary dwelling is two-story, and 20 ft on a lot with a multistory multifamily building.
Setbacks
Side setback
Local rule3 ft
Avalon allows 3 ft side setbacks for all ADUs, more permissive than state minimum.
Rear setback
Local rule3 ft
Avalon allows 3 ft rear setbacks for all ADUs, more permissive than state minimum.
Front setback
Local rule3 ft minimum for ADUs requiring an ADU permit
Front setback for ADUs is 3 ft minimum if an ADU permit is required.
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
1 off-street parking space per ADU, with multiple local exemptions.
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
Local ruleNot required
No replacement required for parking lost due to ADU conversion of garage/carport.
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
Local ruleOnly for a JADU
Owner-occupancy required for JADUs only; not required for ADUs.
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, ADU permit (for new construction or non-conversion), Deed restriction
Deed restriction required before permit issuance; ADU permit required for new construction or non-conversion ADUs.
Avalon-specific factors that can change the answer
State law sets the floor, but these local conditions often decide whether a specific parcel works.
Fire Sprinklers
Sprinklers required in ADU only if required in primary residence; ADU construction does not trigger sprinklers in main house.
Historic District
ADUs in historic districts are exempt from parking requirements.
Hillside Lots
Special height rule: no portion of ADU may exceed 14 ft above upper lot line and 40 ft above natural surface.
Avalon sets lower setbacks (3 ft) and lower detached ADU size caps (850/1,000 sqft) than the state default, and applies special height and parking rules for hillside and historic areas.
Frequently asked questions
Can I build an ADU in Avalon?
Yes. California's statewide ADU law requires Avalon 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 Avalon?
A detached ADU of at least 1,000 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 Avalon?
Side and rear setbacks are limited to 3 ft. 3 ft minimum for ADUs requiring an ADU permit.
Is parking required for an ADU in Avalon?
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 Avalon?
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 Avalon?
Owner-occupancy: only for a jadu. ADUs under 750 sq ft are also exempt from impact fees.
Sources
- Avalon Municipal Code Article 6, §§ 9-5.601–9-5.606 (Ord. No. 1210-23, eff. Feb. 16, 2023; Ord. No. 1228-25, eff. Nov. 13, 2025)
- § 9-5.604(a)(3)-(4)
- § 9-5.606(a)(1)-(3)
- § 9-5.606(c)
- § 9-5.606(g)
- § 9-5.606(g)(3)
- § 9-5.604(a)(1), § 9-5.605(g)
- § 9-5.604(b), § 9-5.605(h)
- § 9-5.605(c)
- § 9-5.606(g)(2)(b)
- § 9-5.605(b)(3)
- 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 § 66311.5 (impact fees: none for an ADU ≤ 750 sq ft or JADU ≤ 500 sq ft)
Last updated February 16, 2023; November 13, 2025. This is an AI-assisted summary of Avalon'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 Avalon Planning before relying on it.
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