Avalon Zoning and ADU Guide for Homeowners

Last updated November 13, 2026. Reviewed by the Cash Home Buyers CA team.

Avalon’s accessory dwelling unit article, Chapter 9-5 Article 6, sets a 500 square foot cap for junior ADUs, 800 square feet for limited detached ADUs, and 850 or 1,000 square feet for larger attached or detached units, and it was most recently amended by an ordinance effective November 13, 2025. This guide summarizes the sizes, heights, setbacks, parking, rental and review rules the city’s code states, and what to do if your home has an older unit or garage conversion.

The code is amended periodically, and the online text notes a further amendment dated 2026, so confirm current rules with Planning before you design.

Avalon ADUs at a glance

Code	Avalon Municipal Code Chapter 9-5, Article 6 (ADUs and JADUs)
Junior ADU size	No more than 500 square feet
Class 1 detached ADU (single-family lot)	800 square feet or smaller; side and rear setbacks at least 3 feet
Class 2 ADU size	850 sq ft (studio or one bedroom) or 1,000 sq ft (two or more bedrooms); attached units limited to 50% of the existing home’s floor area, but never less than 800 sq ft
Height	Detached 16 ft (18 ft near transit; up to 20 ft for roof pitch); attached 25 ft and two stories
Class 2 setbacks	3 feet front, side and rear
Parking	One space per Class 2 ADU or bedroom, whichever is less, with many exceptions
Rental term	Minimum 30 days; no owner-occupancy rule for ADUs; JADUs generally require owner occupancy
Review	Completeness notice within 15 business days; approval or denial within 60 days of a complete application

Unit types and sizes

Article 6 states its purpose as allowing and regulating ADUs and JADUs in compliance with state Government Code. A junior ADU is limited to 500 square feet of interior space. A converted single-family ADU can add up to 150 square feet if the expansion is limited to accommodating ingress and egress.

A Class 1 detached new-construction ADU on a single-family lot is limited to 800 square feet. A Class 2 detached or attached ADU can reach 850 square feet for a studio or one-bedroom unit and 1,000 square feet for a unit with two or more bedrooms.

An attached ADU is limited to 50 percent of the floor area of the existing home, but the code says no percentage limit, floor area ratio, front setback, lot coverage or open space rule may force an ADU below 800 square feet.

Height and setbacks

A detached ADU may not exceed 16 feet, with 18 feet within one-half mile walking distance of a major transit stop or high quality transit corridor, and up to two more feet (a 20 foot maximum) to match the roof pitch of the main home.

A detached unit on a multifamily lot with more than one story above grade may reach 18 feet. An attached ADU may not exceed 25 feet or the zone’s height limit, whichever is lower, and may not exceed two stories.

Height is measured from existing legal grade or the lowest floor, whichever is lower, to the peak.

Class 1 limited detached ADUs need side and rear setbacks of at least three feet. Class 2 ADUs conform to three-foot front, side and rear setbacks, and no setback is required if the unit is built in the same location and to the same dimensions as an existing structure. Converted units must have side and rear setbacks sufficient for fire and safety under the building and fire codes.

Parking, rental and occupancy rules

One off-street space is required for each Class 2 ADU or bedroom, whichever is less, and it may be in a setback area or tandem.

The code lists exceptions, including a unit within one-half mile walking distance of public transit, one inside an architecturally and historically significant historic district, one within the existing home or an accessory structure, one near an established car share stop, and one where the owner or resident does not maintain an autoette under a valid resident vehicle permit. Replacement parking is not required when a garage or carport is converted.

No ADU or JADU may be rented for less than 30 days. ADUs are not subject to an owner-occupancy requirement, but a JADU generally requires the owner to live in either the main home or the JADU, with exceptions where the JADU has its own sanitation facilities or the property is held by a government agency, land trust or housing organization.

Review timeline and fees

The city determines whether an application is complete within 15 business days and gives written notice, then approves or denies a complete ministerial application within 60 days. A denial or an incompleteness determination can be appealed to the Planning Commission, which issues a final written decision within 60 business days.

The article preserves the California Coastal Act, and a coastal development permit, where required, must also be approved or denied within 60 days of a complete application.

The city may charge a processing fee set by council resolution. No impact fee applies to a JADU or to an ADU under 750 square feet, and school fees do not apply to units under 500 square feet. Larger units pay impact fees proportionate to the size of the main home.

Converted ADUs on single-family lots generally avoid new utility connection fees, while other ADUs pay a connection fee or capacity charge proportionate to the burden they create.

State ADU law and Avalon

California’s ADU statute, Government Code section 66314 and following, sets a floor that every city must follow, and local ordinances fill in the details.

The state requires ministerial review within 60 days of a complete application, bars a city from requiring more than a limited set of standards, and generally allows an ADU or conversion inside existing space without added setbacks.

The California Department of Housing and Community Development (HCD) publishes a handbook and keeps a list of the state requirements. Because state law changes often, treat the city’s current ordinance and handout as the final word on size, height, parking and fees for your lot.

ADUs, garage conversions and selling an Avalon house

Many older homes have a converted garage or a backyard unit built without permits. Buyers and lenders ask about them, and California sellers generally disclose known unpermitted work. Our guide to selling as-is with unpermitted work explains the rules, and our Prop 13 guide explains how new construction can affect property tax. Before you list:

• Check city records for permits on any ADU, conversion or addition.
• Ask Planning whether the structure could qualify under current rules.
• Estimate plans, fees and corrections needed to legalize it.
• Compare that with selling as-is and letting a cash buyer take on the legalization.

Questions to ask Planning before you design

• Does my lot and zone allow an ADU, a junior ADU, or both?
• Is a pre-approved or pre-reviewed ADU plan available?
• What are the current impact, utility and school fees for the size I am considering?
• Can my existing garage or accessory structure be converted without changing its footprint?
• Are there fire, slope, easement or utility constraints on my lot?

Junior ADUs and garage conversions in more detail

State law treats a junior ADU as a unit of up to 500 square feet created inside the walls of an existing or proposed single-family home, with an efficiency kitchen and a recorded restriction that keeps it from being sold apart from the house.

A garage conversion is a different path: the unit replaces the garage, and state law generally does not require the city to demand replacement parking. Both are common sources of unpermitted space in older Avalon neighborhoods, which is why buyers’ agents and appraisers ask for the permit record.

If a conversion was done without a permit, the usual fix is to submit as-built drawings, pay the fees and pass inspection, which can take months and cost real money.

Fees, utilities and property tax

State law limits the impact fees a city can charge on smaller ADUs and on conversions of existing space, and it limits when a separate utility connection can be required.

Larger new units can still carry impact fees, school fees and water or sewer connection charges, so ask for an itemized estimate before you commit to plans. New construction is generally reassessed for property tax under Prop 13, which means an ADU can raise the bill for the whole property. Our Prop 13 guide explains how reassessment works.

Why ADUs matter for resale

A permitted ADU can add rental income and appeal for some buyers, but an unpermitted one can complicate financing and appraisal. Lenders typically want permitted living area, and an appraiser may not count unpermitted space.

Because an ADU generally cannot be sold separately from the main home, its value comes through the sale of the whole property.

If you inherited a house with an old backyard unit, or bought one with a converted garage, check what the city has on file before you decide how to sell. Our probate home sale guide covers inherited property.

How to sell a house in Avalon

1. Ask the city for the permit record on any ADU or conversion.
2. Collect plans, inspection records and any city notices.
3. Request a no-obligation cash offer for the house as it stands.
4. Choose your closing date.
5. Close with no repairs, legalization or showings required.

See also our Avalon page, the Avalon as-is sale page, the inherited house page, the Avalon cash offer process and the Los Angeles County hub.

Frequently asked questions

What is the maximum ADU size in Avalon?

A junior ADU is limited to 500 square feet. A limited detached ADU is 800 square feet. Class 2 ADUs can reach 850 square feet for a studio or one-bedroom unit and 1,000 square feet for two or more bedrooms.

What setbacks apply to an Avalon ADU?

Class 1 limited detached ADUs need side and rear setbacks of at least three feet. Class 2 ADUs conform to three-foot front, side and rear setbacks, with no setback needed if built in the same location and dimensions as an existing structure.

Does an Avalon ADU need parking?

One space per Class 2 ADU or bedroom, whichever is less, with exceptions such as transit proximity, a historic district, conversion of existing space, and owners without an autoette permit.

Can I rent my Avalon ADU short term?

No. The code says no ADU or JADU may be rented for a term shorter than 30 days.

How long does Avalon take to review an ADU?

The city gives a completeness determination within 15 business days and must approve or deny a complete application within 60 days. A coastal development permit, where required, is subject to the same 60 days.

Can I sell my Avalon house with an unpermitted ADU or garage conversion?

Yes. You can disclose it and sell as-is, including to a cash buyer. Our statewide guide explains the disclosure rules.

More guides

• We Buy Houses in Avalon
• We Buy Houses in Los Angeles County
• Los Angeles County Property Tax Guide
• Avalon Building Permits Guide
• Avalon Code Enforcement Guide
• Sell an Avalon House As-Is
• Avalon Cash Offer Process
• All California Guides

Sources

• City of Avalon Municipal Code: Article 6 Accessory Dwelling Units (eCode360)
• California HCD: Review of the City of Avalon’s ADU ordinance
• California HCD: Accessory Dwelling Units
• City of Avalon: Staff Directory

This guide is general information from public sources, not legal advice. Confirm current rules, fees and hours with the city.