Santa Monica Zoning and ADU Guide for Homeowners and Sellers

Last updated November 13, 2026. Reviewed by the Cash Home Buyers CA team. Information comes from the City of Santa Monica; sources are listed at the end.

Santa Monica describes ADUs as legal secondary units allowed on residential and mixed-use properties, and publishes an ADU and JADU Guide for parcels already developed with a home. The city also runs a Preapproved ADU Program for detached units.

Santa Monica zoning and ADU at a glance

How do I find out what is allowed on a Santa Monica lot?

Start with the city’s Accessory Dwelling Units page and the ADU and JADU Guide, and ask Planning what applies to your parcel. Zoning standards such as building height and footprint can differ by zone, so do not rely on a general summary.

What are the ADU rules in Santa Monica?

The city’s ADU page says regulations for establishing ADUs and junior ADUs are published there, and the November 2025 ADU and JADU Guide covers parcels with an existing home. Older city materials list different size limits, which is a reminder that these rules have changed and will keep changing with state law. Confirm current size, setback and parking rules with the city before relying on any figure.

Selling a Santa Monica house with an ADU or converted garage

A permitted ADU is part of the property and can matter to buyers. An unpermitted unit is different: a buyer’s inspector or lender may notice a unit that does not match the records. See our Santa Monica building permits guide and code enforcement guide.

How to sell a house in Santa Monica with an ADU or zoning problem

1. Ask the city what permit records exist for the unit or garage conversion.
2. Check the ADU guide for rules that apply to the lot.
3. Compare options: legalize the unit, sell with a price credit, or sell as-is to a cash buyer who prices the risk in.
4. Disclose honestly. Known unpermitted work should be disclosed.

We buy Santa Monica houses as they are. See how we buy houses in Santa Monica or our cash home buyer page.

Not sure what your zoning or unit means for a sale? Call (424) 435-2326 or request a cash offer. There is no cost and no obligation.

What the city’s November 2025 ADU and JADU Guide says

The city’s ADU and JADU Guide for parcels with a single-unit dwelling (the file is dated 11-25) sets out concrete standards. These are the figures it states; confirm them with Planning before you rely on them, because state and local rules keep changing.

For JADUs and R1 ADUs, a deed restriction must be recorded, which the guide says involves completing an online application and scheduling a virtual Planning submittal appointment. The guide does not state fee amounts, so ask the city for current fees.

What this means when you sell

A few of these points matter more at sale time than others. The deed restriction is part of the record a buyer’s title company will see, so ask whether one was recorded for your unit.

The owner-occupancy rule for JADUs means a buyer who wants to rent out both the main house and a JADU may not be able to, which can affect how buyers value the property.

And because the guide treats existing unpermitted structures built before January 1, 2020 favorably for setback purposes, a converted garage or backyard structure may be easier to legalize than owners assume, though it still needs a building permit. Ask Planning and Building and Safety what it would take for your specific structure.

Questions to ask the city about your unit

• Is the structure on record as an ADU, a JADU, or an accessory building?
• Was a deed restriction recorded, and is the owner-occupancy requirement tied to my property?
• If the unit was built without a permit, can it be legalized as a converted ADU, and what inspections would be required?
• Is my parcel in the Coastal Zone or on the California Register of Historical Resources, either of which can add steps?

Santa Monica zoning and ADU FAQ

Does Santa Monica allow ADUs?

Yes. The city describes ADUs as legal secondary units allowed on residential and mixed-use properties.

Does Santa Monica have preapproved ADU plans?

Yes. The Preapproved ADU Program offers standard plans, which are only permitted for detached ADUs.

Where is the city’s ADU guide?

The ADU and JADU Guide for parcels with an existing home is a PDF on the city’s website.

Can I sell a house in Santa Monica with an unpermitted ADU?

Yes. It can complicate a traditional sale, so disclose it and choose between legalizing it, discounting the price, or selling as-is to a cash buyer.

Does Santa Monica require parking for an ADU?

The city’s November 2025 guide says on-site parking is not required, and parking removed to create an ADU does not need to be replaced.

How large can a Santa Monica ADU be?

The guide lists 850 square feet for a studio or one-bedroom and 1,200 square feet for two or more bedrooms, with JADUs capped at 500 square feet. Confirm current figures with Planning.

Sources

• City of Santa Monica: Accessory Dwelling Units
• City of Santa Monica: ADU and JADU Guide
• City of Santa Monica: Preapproved ADU Program

This guide is general information, not legal advice. ADU and zoning rules change; confirm with the City of Santa Monica.