San Diego 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 San Diego Development Services Department; sources are listed at the end.

In the City of San Diego, a building permit is required to create an accessory dwelling unit (ADU) or junior ADU, with no exemptions, and your property’s zone decides what else you can build. If you own a house with a backyard unit, a converted garage or a room that has been rented out, whether that space was permitted changes how you sell it.

San Diego ADU rules at a glance

Who regulates	City of San Diego Development Services Department (inside city limits)
Permit needed?	Yes. A building permit is required for every ADU or JADU, with no exemptions
Find your zone	The city’s Zoning and Parcel Information Portal (ZAPP)
Single-family lots	One primary home, one ADU attached or detached, one ADU converted from existing space, and one JADU
JADU size	No more than 500 square feet, inside an existing single-family residence
Short-term rental	Not allowed. An ADU or JADU cannot be rented for fewer than 31 consecutive days
Coastal areas	A Coastal Development Permit is required for many ADUs in the Coastal Overlay Zone
Unpermitted units	A streamlined legalization program exists for units built before January 1, 2020

How does zoning decide what you can build in San Diego?

Every parcel in the city has a zone, and the zone sets the use, height, setbacks and floor area.

The city’s Development Services Department tells owners to look up their zone on the Zoning and Parcel Information Portal, known as ZAPP, which also shows overlay zones such as the Coastal Overlay Zone.

Base zones are in Chapter 13 of the San Diego Municipal Code, and planned district zones are in Chapter 15.

For sellers, the zone matters because it tells you what the lot legally allows today and what a buyer could add. An ADU still has to meet the front yard setback of the zone, must stay within the zone’s height limit (two stories in single dwelling unit zones), and counts toward the lot’s floor area ratio. ADUs do not count toward density.

How many ADUs can a San Diego lot have?

The city’s Information Bulletin 400 lists what a single dwelling unit zone allows: one primary dwelling, one ADU attached to or detached from the home, one ADU converted from existing space or an accessory structure, and one junior ADU.

Lots with existing multi-unit buildings follow the multiple-dwelling rules, which allow more units. The city also runs an ADU Home Density Bonus Program that allows extra “bonus” ADUs when a qualifying deed-restricted affordable ADU is built, with rules set out in the municipal code.

• Parking: generally not required for new ADUs, with exceptions such as garage conversions in the Beach Impact area of the Parking Impact Overlay Zone and certain affordable or bonus ADUs outside transit priority areas.
• Fire sprinklers: attached ADUs and JADUs need them when the main home is sprinklered. Detached ADUs are exempt only when the main home has none.
• Rentals: no stays under 31 consecutive days.
• Fees: vary by project, and ADUs are not exempt from the city’s inclusionary housing regulations.

What if the ADU in my San Diego house was never permitted?

The city has a streamlined program to legalize unpermitted ADUs and JADUs, described in Information Bulletin 242. It applies to units in the City of San Diego built without a building permit before January 1, 2020, and the unit must meet the state definition of an ADU.

Submittals include the unit’s location on the property, clearly marked and dimensioned, along with plans. Legalizing takes time and money, and the work may require changes to bring the unit up to code.

If you do not want to go through that before selling, you have two other paths: sell with a price reduction and let the buyer handle it, or sell as-is to a cash buyer. Either way, in California you generally have to disclose what you know about unpermitted work.

Can an ADU be sold separately from the main house?

Not as a simple lot split. Under the city’s rules, an ADU can be sold on its own only if it is converted to a condominium, which requires a subdivision process, final approval of the ADU’s inspections, lienholder consent and a recorded covenant.

Some ADUs, such as those financed by the San Diego Housing Commission or restricted to lower-income renters, cannot be sold separately for the length of their restriction. For most homeowners the ADU sells together with the main house.

How to sell a house in San Diego with an ADU or zoning issue

1. Check the zone and permit history. Look up the parcel in ZAPP and ask Development Services for permit records so you know what is on file.
2. Decide whether to legalize. Compare the cost and time of the legalization program with what the unit adds to the sale price.
3. Disclose honestly. Tell buyers about work done without a permit.
4. Choose your sale route. List with the unit as-is or permitted, or take a cash offer with no repairs, inspections or showings.

We buy San Diego houses as they are, including ones with unpermitted units. See how selling a house as-is in San Diego works, or read about our San Diego cash-offer process. If the city has cited the property, see our San Diego code enforcement guide.

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

San Diego zoning and ADU FAQ

Do I need a permit to build an ADU in San Diego?

Yes. The city requires a building permit to create an ADU or JADU, with no exemptions.

How do I find my property’s zone in San Diego?

Use the city’s Zoning and Parcel Information Portal (ZAPP), which shows the zone and overlay zones for a parcel.

Can I use my San Diego ADU as a short-term rental?

No. The city says an ADU or JADU may not be rented for fewer than 31 consecutive days.

Can I legalize an unpermitted ADU in San Diego?

Often yes. The city offers a streamlined permit program for ADUs and JADUs built without a permit before January 1, 2020, described in Information Bulletin 242.

Can I sell a San Diego house with an unpermitted ADU?

Yes. Disclose the unit, then choose between legalizing it, discounting the price, or selling as-is to a cash buyer.

Sources

• City of San Diego: Information Bulletin 400, ADUs and JADUs
• City of San Diego: ADU/JADU program page and FAQ
• City of San Diego: Information Bulletin 242, legalizing unpermitted ADUs
• City of San Diego Planning: Accessory Dwelling Units

This guide is general information, not legal advice. Zoning and ADU rules change; confirm requirements with the City of San Diego Development Services Department.