All ADU Regulations

San Diego, California

The City of San Diego has updated its ADU ordinance to comply with new state laws. Below are the up-to-date requirements for permitting an ADU in the City of San Diego.

April 25, 2023
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San Diego

From the picturesque bluffs of Point Loma to the sun-drenched neighborhoods around Old Town, La Jolla, and beyond, the City of San Diego is the perfect place to build an ADU. Homeowners in San Diego are prime for building ADUs that open outwards and let in the sea breeze and warm California sunshine.

General ADU requirements

Your home doesn’t need to be of a minimum size for you to start building an ADU on your property. So, assuming you are eligible, you can build one no matter how small or large your existing home is.

The smallest ADU allowed is 150 sq.ft., but this minimum increases with the number of bedrooms you are planning to include.

Detached, attached, conversion, and Junior ADUs (JADUs) can be built wherever permitted, and the type of ADU you are building would determine its specific requirements. You can also stack ADUs on top of each other or attach two ADUs to each other.

Generally speaking, however, it’s ideal to match the design of your ADU to the design of your primary dwelling and keep roof forms, materials, and other architectural details similar.

ADUs must be equipped for independent living and have permanent facilities for:

  • Living
  • Eating
  • Sleeping
  • Sanitation
  • Cooking
  • Exterior access that is separate from the primary dwelling

ADU kitchens must also have:

  • A sink with running water
  • Countertops and cabinetry
  • A refrigerator
  • A permanent range/cooktop

Similar to attached ADUs, JADUs must have a separate entrance from that of the primary dwelling. However, JADUs may share bathroom/sanitation facilities with the primary dwelling.


All properties zoned for single-family and multifamily use may be eligible to build ADUs.


There are a number of fees associated with building your ADU and the exact amounts would depend on the scope of your project (among other factors). In San Diego, fees can be around $9,000. In some zoning areas, certain fees have been waived to reduce the overall cost of your project, so speak to your Cottage consultant to learn about how this applies to you.

Here are some of the fees you can expect to pay:

  • Plan check fees
  • Residential, building, and green code fees
  • City impact fees (for ADUs above 750 sq.ft.)
  • School impact fees
  • Permit fees

The first step to building an ADU In the City of San Diego is submitting your ADU plans for a pre-plan check review. Typically within 10-20 days after submission, you’d be invoiced for a plan check fee. Once paid, the city will conduct its first review of your plans.

During this stage, they will note any corrections that need to be made, and typically get back to you within 60 days. All resubmissions after this point usually take up to 30 days to review.

Once your plans are approved, it’ll take another 20-25 days for them to be processed. It is during this processing period that you are expected to pay Residential, Impact, and other permitting fees.

Coastal Development Permit (CDP)

If you are building in a coastal zone within the City of San Diego, like Point Loma or North County, you would need to get a CDP through the California Coastal Commission. General state laws don’t necessarily cover the specifics of building in coastal areas, and a CDP ensures compliance with coastal zone regulations. This is a recent change, put forward in September 2022.

Number of units

Lots zoned for single-family use are permitted to add one ADU (either attached or detached) and one Junior ADU (JADU). Assuming you are in line with zoning requirements, you may even be able to build one “affordable” (or income-restricted) ADU and one unrestricted ADU through the San Diego ADU Bonus Program. This limit applies to properties outside the Transit Priority Area (TPA). If your property is within the TPA, you may build as many “bonus” ADUs as space permits.

All things considered, you may be eligible to build four (or more) ADUs on single-family properties, while two detached and “bonus” ADUs are allowed on multi-family zoned properties that qualify as “low/moderate income housing”.

There is no limit to the number of conversion ADUs you can create on your property, i.e. you may convert non-livable areas like basements, attics, and garages into ADUs. Conversion projects are considered in addition to the allowed number of detached ADUs.

Building size

Unlike some other jurisdictions, the City of San Diego doesn’t tie ADU eligibility to the size of your primary dwelling. Both detached and attached ADUs may be up to 1,200 sq. ft., regardless of the size of your primary dwelling.

Lot coverage isn’t an issue if you are building an ADU of 800 sq. ft. or less – you can build one even if you exceed this ratio.

You may build a JADU so long as it's contained within an existing accessory structure, like a garage or a basement.

Building height

The minimum height for a detached ADU is 16 ft and the maximum allowed height for most residential properties varies between 24 ft. and 30 ft. You may build a two-story ADU or stack ADUs on top of each other if it meets this requirement.

If you are building an attached ADU on top of an existing accessory structure, you may build up to 21 ft. or 30 ft. for flat-roofed and sloped-roofed structures, respectively.


If your ADU meets the 16 ft. height limit, you can build up to the property line, with side and rear setbacks of 0 ft.

If you share a property line with another residentially zoned property, your ADU must maintain side and rear setbacks of 4 ft. if it exceeds 16 ft. in height or has more than one story.

If you are converting an existing space into an ADU or demolishing an existing space to make room for an ADU, you may observe the setback regulations of the original structure.

Detached ADUs and projects that add floor area to an existing structure should abide by zone-specific setback requirements.

All external staircases must be at least 5 ft. from the property line.

Fire safety

Maintaining setbacks of at least 5 ft. is recommended for fire safety, and saves you thousands of dollars otherwise needed to make your ADU fire-rated.

If your ADU is less than 10 ft. from an existing structure, you would need additional materials to ensure a fire-safe build.


A parking space is not required for an ADU if:

  • It is located within one-half mile walking distance from public transport
  • It is within an established historic district
  • It was converted from an existing structure or is attached to the primary dwelling

If parking is needed, it may be located in an existing driveway as tandem parking, so long as it is within the setbacks.

If a parking space was lost to make room for/convert into an ADU, it does not need to be replaced.


As of December 2020, owner occupancy is only required in the City of San Diego if the property has both an ADU and a JADU. This means the homeowner has to live on-site in either the JADU or the primary residence if they wish to rent out their ADU.

In other instances, owner occupancy is not required.


While long-term rentals are permitted for ADUs, short-term rentals under a period of 30 days are not allowed in the City of San Diego. Depending on its neighborhood and the number of bedrooms your ADU has, you may be able to earn anywhere from $1,500-$4,000 in monthly rental income.


Do you have a utility easement over your property? Are you in the coastal zone? Reach out to us and we’ll help you build a custom ADU to fit your unique property characteristics and local regulations!


How much does it cost to add an ADU in the City of San Diego?

All in all, the total cost of building an ADU in the City of San Diego can range between $100,000 for a studio/one bedroom and $400,000 for larger ADUs. This includes permitting fees and depends on the size of your ADU and the location of your property. Construction makes up 90% of your total costs and varies based on property specifics, project scope, and cost per sq. ft. The first few hundred sq. ft. are the most expensive, and the cost per sq. ft. reduces as you scale up! As always, additional customization and higher-end designs are likely to cost more.

Can I build an ADU on my property in San Diego?

Yes, most single-family and multi-family properties are eligible for an ADU.

How much can you rent an ADU for in the City of San Diego?

Depending on the exact neighborhood you are building an ADU in, its size, and its features, you may be able to earn anywhere from $1,500-$2,600 for a one-bedroom, $2,300-$3,400 for a two-bedroom, and $2,400-$4,000 for a three bedroom.

How long does it take to permit an ADU in the City of San Diego?

The overall permitting timeline in the City of San Diego is 6-8 months. This process includes a pre-screen and plan check, and may take longer if you are building in a coastal zone.

Can an ADU be two stories in the City of San Diego?

Yes. As long as it meets residential property height requirements, you may build a two-story ADU.

Design and build with confidence.