Accessory Dwelling Unit's Regulations in San Diego

San Diego County accessory dwelling unit regulations vary from city to city. Here you will find the regulations set by your governing city within San Diego County. In general, regulations are similar but vary slightly from city to city. In an effort to combat California’s housing shortage and rising housing costs, California passed major legislation to further streamline and incentivize homeowners to build ADU’s. In recent years several laws have passed to cut the red tape around constructing ADU’s, making it easier for homeowners to build. ADU’s in San Diego are becoming very popular due to rising housing costs and shortage of rental homes in San Diego. Making it a very appealing investment for homeowners.

San Diego ADU Regulations

What size ADU is allowed? How big?

An ADU is intended to be secondary in size to the single-family residence. An ADU attached to a primary dwelling may be up to 50% of the size of the single-family residence, up to a maximum of 1,200 square feet. An ADU detached from the single-family residence may be up to 1,200 square feet, regardless of the size of the residence.

Examples for the allowed sizes are provided below:

Existing single-family residence of 1,800 sq. ft. x 50% would allow an attached ADU of up to 900 square feet.
Existing single-family residence of 3,000 sq. ft. x 50% would be 1,500 square feet, but an attached ADU would be allowed up to a maximum of 1,200 square feet.
Single-family residence of 1,800 sq. ft. would allow a detached ADU of up to 1,200 square feet.

Do I need to provide additional parking for a new ADU?

Although, an ADU shall provide only one parking space, appropriate parking should be considered when designing your ADU. The parking space for the ADU may be located in an existing driveway as tandem parking as long as the required parking space(s) complies with the required front yard and/or exterior side yard setback(s).

Alternatively, if an ADU is located within ½ mile from a bus stop, no additional parking is required.

May I convert an existing accessory structure into an ADU?

Yes, any permitted existing accessory structure such as a garage, workshop, guest living quarters, accessory living quarters, or accessory apartment, etc. may be converted into an ADU regardless of lot coverage, setbacks regulations.

What if I want to convert my garage to an ADU, do I need to replace the parking?

Yes, when converting a garage to an ADU the property must replace the parking spaces being lost by the conversion, in addition to the one parking space required for the new ADU. An existing single-family residence requires at least 2 parking spaces. The replacement parking may be in any configuration including tandem, within the side or rear yard setback areas, or on a driveway, but it cannot be in the front yard or exterior side yard setbacks.

What are the height limitations for the ADU?

A detached ADU is limited to 2 stories and 24’ in height. May I sell or rent my ADU? An ADU cannot be sold separately from the existing single-family residence, but there is no restriction on who may rent the ADU. However, an ADU shall not be used or rented for less than 30 days.

Del Mar ADU Regulations

Zoning

Under the adopted Ordinance, Accessory Dwelling Units are allowed in all residential zones EXCEPT RM-South (Medium Density Mixed Residential-South). They are also allowed in the Carmel Valley Precise Plan Specific Plan (CVPP). Junior Accessory Dwelling Units are only allowed in the following zones:

CVPP, R1-10, R1-10B, R1-14, R1-40, R1-5, R1-5B

Size Limits

ADUs may not exceed 550 square feet, while JrADUs may not exceed 500 square feet Additionally, an ADU may not be more than 14 feet in height., with the exception that an ADU and a JrADU may be located on the second floor within an existing dwelling unit. A JrADU is always entirely contained within, and accessory to an existing single dwelling unit and involves no exterior development.

Does the square footage count toward Floor Area Ratio (FAR)?

Yes, both an ADU and a JrADU will count toward FAR. However, the size of an ADU is measured in terms of habitable floor space, which is then added to the existing floor area. The total of these two calculations must comply with the zone maximum.

Can I rent my ADU/JrADU?

ADUs and JrADUs may be rented for 30 consecutive days or greater, unless located in the RC zone, in which they may be rented without limit.

Is parking required?

Most properties will not be required to dedicate a parking space for an ADU, unless located more than 1/2 mile from a public transit stop. Please view the map (PDF), and if your property is highlighted, you will be required to designate a parking space for the ADU. No parking is required for a JrADU.

Can I have more than one ADU/JrADU on a lot?