La Jolla · Remodel guides · Process

Backyard homes (ADUs) and junior units in La Jolla: City permits and coastal rules

An ADU is a second, smaller home on the same lot, like a backyard cottage. A junior ADU (JADU) is a small unit inside the main house. This guide explains the City of San Diego rules, including the extra coastal rules that cover much of La Jolla.

I’m Weston Clark, Founding Member of the Dickinson-Clark Team at Compass. I help owners and buyers in La Jolla and coastal San Diego read these rules in plain words. Check them with the City, a lawyer and coastal staff before you count on rent, a payback, or a timeline. You can talk about fees with Weston directly. This form does not give a commission quote.

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Related: Remodel rules · Historic review · La Jolla

What ADU and JADU mean

ADU stands for Accessory Dwelling Unit. JADU stands for Junior Accessory Dwelling Unit. This page sums up the City’s published rules for them. It is not advice to build and does not predict rent or returns.

• What an ADU is
• What a JADU is
• The Coastal Overlay Zone, and why La Jolla often has different rules
• Building permits and coastal permits
• Where to read more: remodel rules, historic review and La Jolla

Our main sources are City Information Bulletin 400 (IB 400, January 2026), a City handout on ADUs. We also use the San Diego Municipal Code (the city’s written laws), Chapter 14, Article 1, Division 3 (section 141.0302), and the City’s code update pages. They do not replace advice on your lot.

What an ADU is

IB 400 says an ADU is a home, attached to the main house or separate, that:

• Is 1,200 square feet or less;
• Has everything needed to live on its own: space to live, sleep, eat and cook, and a bathroom; and
• Sits on a lot with a house or apartments, now or planned.

The main rules are in the Municipal Code, Chapter 14, Article 1, Division 3 (including section 141.0302). ADUs are allowed where the zoning tables list them, which is usually where homes are allowed. Check the zone for your lot with the City’s online map tool (ZAPP) and a lawyer.

Size: IB 400 sets a minimum of 150 square feet and a maximum of 1,200 square feet for an attached or separate ADU. Some conversions of existing space have their own limits.

What a JADU is

IB 400 says a JADU is a unit of at least 150 square feet and no more than 500 square feet. It sits inside a house (now or planned) or an attached garage, on a single-home lot. It may have its own bathroom or share one with the house. It must have a kitchen, which can be a small one.

More City rules for JADUs:

• Its own outside door, separate from the main house
• Its own kitchen, full or small
• Its own bathroom or a shared one
• It cannot be sold apart from the main house
• It must be rented for more than 30 days at a time, so no short-term rentals

Check current rules for your lot with the City and a lawyer.

The Coastal Overlay Zone matters in La Jolla

The Coastal Overlay Zone is an extra map layer near the coast with its own rules. Much of La Jolla is in or near it. IB 400 says plainly that some of its rules do not yet apply in the Coastal Overlay Zone.

• On Sept. 12, 2024, the California Coastal Commission approved ADU rules in Housing Action Package 1.0 (O-21439). ADUs in the coastal zone must now follow its setback rules (how far a building must sit from the lot line) and landscape rules.
• Other rule packages apply in the coastal zone only after the Coastal Commission approves them. IB 400 lists O-21618, O-21758, O-21836 and O-21989 as still waiting.
• The City’s 2026 Code Update (O-22109) took effect July 15, 2026 outside the coastal zone. Inside it, it is not yet approved.
• The 2025 ADU and JADU changes (O-21989) took effect outside the coastal zone on August 22, 2025. Inside it, the City says they are not yet approved.

Check the rules for your lot with the City, coastal staff or a lawyer.

See also La Jolla remodel rules for coastal remodels, and La Jolla historic review for buildings 45 years or older.

Building permits and coastal permits

Building permit: IB 400 says you always need a building permit to create an ADU or JADU. There are no exemptions. The permit type depends on how many units you add (see City Information Bulletin 125). You apply online through the City’s permit portal.

Coastal Development Permit (CDP): a CDP is a coastal building permit. In the coastal zone, you need one if the unit is not fully inside the existing house, adds living space, or turns non-living space into living space. Since Sept. 7, 2022, units in the non-appealable part of the zone (where a City decision cannot be appealed to the state) may get a City CDP if set tests are met. Then the City may issue it as a simple building permit (“Process One”). A JADU in the coastal zone does not always need a CDP. Some qualify for an exemption under code section 126.0704. Check your site with the City, coastal staff or a lawyer.

Preapproved plans: under a state law (AB 1332), you can use plans the City has already approved. They get a set review time and must still meet city rules. They are not a promise of approval.

Parking: IB 400 says ADUs outside the coastal zone need no parking. Inside it, parking rules differ, for example near beaches or transit. Check your lot with the City.

Where this fits with other guides

You can talk about fees with Weston directly. This form does not give a commission quote.

Related guides

Talk with Weston about adding an ADU

Tell me where you are with an ADU or JADU idea for a La Jolla or coastal San Diego home. I can walk you through the City’s rules, and the City and a lawyer can confirm them.

Or call (858) 997-8998 · weston@sandiego.homes · Search on Compass

Sources

• City of San Diego — Information Bulletin 400 (Jan 2026) ADU / JADU
• City of San Diego — SDMC Ch.14 Art.1 Div.3 (§141.0302)
• City of San Diego — Adopted LDC Updates · Single-Issue LDC Amendments
• HUD — Fair Housing Act overview
• Internal: remodel rules, historic review, La Jolla