County of San Diego ADU Regulations & Zoning

, California

Zip Codes: 91902, 91977, 92003, 92014, 92021, 92026, 92027, 92028, 92029, 92058, 92059, 92067, 92071, 92081, 92082, 92084, 92091, 92127
Neighborhoods: Bonita, Bonsall, Fairbanks Ranch, Fallbrook, Hidden Meadows, Lakeside, Pala, Pala Mesa, Pauma Valley, Rancho Santa Fe, Rainbow, Valley Center

Unincorporated areas (listed above) are covered by the County of San Diego's ADU rules and regulations. Additionally, some city properties are subject to County of San Diego ADU rules and regulations. This will depend on whether your city has incorporated the land on which your property is located. In some cities like Vista, San Marcos, Escondido, Oceanside, Encinitas, Del Mar, Chula Vista, El Cajon, Santee, and parts of San Diego, portions are regulated by County of San Diego and not the city. If you don't know what jurisdiction applies to your property, we will look that up for you in early phases of our discussions.

The County requires in-person submission of plans, which adds some processing time and expense. Review times are moderate. The County has also put out some standard floor plans, which some homeowners have found helpful as a starting place for their ADU designs.

Turnaround times at the city are moderate to long, and include a pre-screen component before plans will be reviewed. Fortunately, plan check fees have been waived. The County of San Diego requires in-person submissions, which does add some processing time and expense. Other agencies that are more proximate to the location of the residence may require input and approval (i.e., local fire agencies).

County of San Diego Regulation & Permitting Requirements:

  • ADU SIZE & BUILDING CONSTRAINTS

    What size detached ADU can you build in County of San Diego?

    County of San Diego allows for a detached ADU up to 1200 sqft. ADUs up to 800 square feet are exempt from lot coverage requirements. (Meaning: You can build an ADU of this size even if you’re maxed out on lot coverages).

    What is the height requirement for an ADU in County of San Diego? Can you build a 2-story ADU in County of San Diego?

    The height of a detached ADU can be up to 24′ and two stories.

    Does County of San Diego allow roof decks on ADUs?

    No, roof decks are not permitted on detached ADUs in County of San Diego.

    How big can an attached ADU be in County of San Diego?

    The square footage of any attached ADU may not to exceed 50% of the primary dwelling square footage, or 1,200 sqft, whichever is less, but not less than 800 square feet.

    What are the requirements of the exterior of the ADU?

    The exterior roofing, trim, walls, windows and the color palette of the ADU shall incorporate the same features as the primary dwelling unit.

  • SETBACKS

    What is the setback requirement for an ADU in County of San Diego?

    ADUs must comply with the required front & exterior side yard setbacks and a minimum side and rear setback of at least 4’ (except any required fire setbacks).

    What is the minimum distance the ADU must be from existing structures?

    The minimum required distance between structures is 6′, with 4′ eave to eave.

  • ADDITIONAL REQUIREMENTS

    Does County of San Diego require in-person submission of plans for an ADU?

    Yes, County of San Diego requires in-person submission of plans and does not accept digital applications at this time.

    Does County of San Diego require a soils report for an ADU?

    Yes, County of San Diego requires a soils report for ADUs of 500sqft or more.

    Does County of San Diego require coastal development permits?

    No County areas are subject to Coastal requirements.

  • MULTIFAMILY

    How many ADUs does County of San Diego allow for multifamily properties?

    Up to two detached ADUs may be permitted per lot that has an existing multifamily complex. This is subject to the detached ADUs being limited to a height of 16′ and 4’ rear yard and side setbacks.

    Can you stack detached ADUs on top of each other?

    No, you cannot stack ADUs on top of each other in County of San Diego.

    Can you attach two ADUs to each other in County of San Diego?

    No, you cannot attach two ADUs. The County has interpreted that multi-family lots are permitted two freestanding, detached accessory dwelling units which are detached from the multi-family residence as well as from one another.

    Can you convert existing space to an ADU?

    Yes, existing non-livable space may be converted to ADUs (e.g. storage areas and garages). The minimum number of ADU conversions allowed is one, up to a maximum equal to 25% of the number of existing multifamily units. This is in addition to the allowed number of detached ADUs.

  • PARKING

    What is the parking requirement for an ADU in County of San Diego?

    A parking space is not required for an ADU in any of the following instances:
    o Within a one-half mile walking distance from public transit, which includes bus stops.
    o Within an established historic district.
    o Converted from the existing space of a primary residence or accessory structure, or are attached to an existing or proposed primary residence.

    Where can a parking space be located?

    If a parking space is required, it may be located within the setbacks and in an existing driveway as tandem parking. Parking spaces don’t need to be replaced when a garage, carport, or covered parking structure is demolished in conjunction with the construction of an ADU or converted to an ADU.

County of San Diego ADU Projects:

$275,000

Permitting
Vía Calvillo
Bonsall, California 92003
2 Bed • 2 Bath • 990 ft2

$320,000

Design
Via Del Alba
Rancho Santa Fe, California
2 Bed • 2 Bath • 1,200 ft2

$295,000

Design
Anderson Street
Bonita, California 91902
3 Bed • 3 Bath • 1,200 ft2

County of San Diego Regulation & Permitting Requirements:

  • ADU SIZE & BUILDING CONSTRAINTS

    What size detached ADU can you build in County of San Diego?

    County of San Diego allows for a detached ADU up to 1200 sqft. ADUs up to 800 square feet are exempt from lot coverage requirements. (Meaning: You can build an ADU of this size even if you’re maxed out on lot coverages).

    What is the height requirement for an ADU in County of San Diego? Can you build a 2-story ADU in County of San Diego?

    The height of a detached ADU can be up to 24′ and two stories.

    Does County of San Diego allow roof decks on ADUs?

    No, roof decks are not permitted on detached ADUs in County of San Diego.

    How big can an attached ADU be in County of San Diego?

    The square footage of any attached ADU may not to exceed 50% of the primary dwelling square footage, or 1,200 sqft, whichever is less, but not less than 800 square feet.

    What are the requirements of the exterior of the ADU?

    The exterior roofing, trim, walls, windows and the color palette of the ADU shall incorporate the same features as the primary dwelling unit.

  • SETBACKS

    What is the setback requirement for an ADU in County of San Diego?

    ADUs must comply with the required front & exterior side yard setbacks and a minimum side and rear setback of at least 4’ (except any required fire setbacks).

    What is the minimum distance the ADU must be from existing structures?

    The minimum required distance between structures is 6′, with 4′ eave to eave.

  • ADDITIONAL REQUIREMENTS

    Does County of San Diego require in-person submission of plans for an ADU?

    Yes, County of San Diego requires in-person submission of plans and does not accept digital applications at this time.

    Does County of San Diego require a soils report for an ADU?

    Yes, County of San Diego requires a soils report for ADUs of 500sqft or more.

    Does County of San Diego require coastal development permits?

    No County areas are subject to Coastal requirements.

  • MULTIFAMILY

    How many ADUs does County of San Diego allow for multifamily properties?

    Up to two detached ADUs may be permitted per lot that has an existing multifamily complex. This is subject to the detached ADUs being limited to a height of 16′ and 4’ rear yard and side setbacks.

    Can you stack detached ADUs on top of each other?

    No, you cannot stack ADUs on top of each other in County of San Diego.

    Can you attach two ADUs to each other in County of San Diego?

    No, you cannot attach two ADUs. The County has interpreted that multi-family lots are permitted two freestanding, detached accessory dwelling units which are detached from the multi-family residence as well as from one another.

    Can you convert existing space to an ADU?

    Yes, existing non-livable space may be converted to ADUs (e.g. storage areas and garages). The minimum number of ADU conversions allowed is one, up to a maximum equal to 25% of the number of existing multifamily units. This is in addition to the allowed number of detached ADUs.

  • PARKING

    What is the parking requirement for an ADU in County of San Diego?

    A parking space is not required for an ADU in any of the following instances:
    o Within a one-half mile walking distance from public transit, which includes bus stops.
    o Within an established historic district.
    o Converted from the existing space of a primary residence or accessory structure, or are attached to an existing or proposed primary residence.

    Where can a parking space be located?

    If a parking space is required, it may be located within the setbacks and in an existing driveway as tandem parking. Parking spaces don’t need to be replaced when a garage, carport, or covered parking structure is demolished in conjunction with the construction of an ADU or converted to an ADU.

County of San Diego ADU Projects:

$275,000

Permitting
Vía Calvillo
Bonsall, California 92003
2 Bed • 2 Bath • 990 ft2

$320,000

Design
Via Del Alba
Rancho Santa Fe, California
2 Bed • 2 Bath • 1,200 ft2

$295,000

Design
Anderson Street
Bonita, California 91902
3 Bed • 3 Bath • 1,200 ft2