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Carlsbad ADUs

Everything about building Accessory Dwelling Units in Carlsbad, CA

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495 sqft

1,157 sf
2 Beds
The city government of Carlsbad has updated its local zoning codes to comply with the State ADU mandate.
The California Building Code (CBC) 2019 is adopted.

Last Updated 09/19/21


City Hint: The City of Carlsbad permitted a total of 77 ADU projects in the past year of 2020.

Number of ADUs allowed:

One ADU is allowed, either attached to an existing or proposed single-family (main) residence or detached and on the same legal lot as the main residence.

Types of ADUs allowed:

Detached ADU, Attached ADU, Junior ADU are approved. ADUs may be new construction or converted from existing space. JADUs must be converted from existing space.

Lot size:

Residential lots will not be subject to any minimum lot size for Accessory Dwelling Unit (ADU)s by ordinance or of the underlying zoning district. ~ Updated: State Law AB-68

ADU size:

Attached ADUs are ADUs that add more than 150 square feet to the main residence.

If attached to the main residence, an ADU shall not exceed 50% of the total floor area of the main residence, or 1,200 square feet, whichever is less (unless this results in an ADU of less than 800 square feet).

If detached from the main residence, an ADU is allowed up to 1,200 square feet.

JADU's are allowed at a maximum of 500 square feet in size.


Four-foot minimum setbacks from rear and side yard property line. Front yard setback and required building separation per zoning standards.

Existing setbacks can be maintained for an existing legal detached garage or existing accessory structure that is converted to an ADU on a lot with
a single-family residence.

Setbacks for new ADU can conform to those of a legally demolished structure, provided that the construction of the proposed ADU is built in the same location and to the same dimensions per applicable zoning standards.

ADU setback separation must meet all applicable fire and safety standards.


An ADU shall provide one parking space. The parking space 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.

A parking space is not required for an ADU in any of the following instances:
• ADUs within a one-half mile walking distance from public transit, which includes bus stops.
• ADUs within an established historic district.
• ADUs within an area where on-street parking permits are required, but not offered to the ADU occupants or ADU is located within one block of a
car share area.
• ADUs that are converted from the existing space of a primary residence or accessory structure, or are attached to an existing or proposed primary residence.
• ADUs covered under the mandatory approval requirements of Government Code Section 65852.2(e).

Fire Safety:

When proposed on a lot adjoining native vegetation, accessory structures within a fire suppression zone must be reviewed and approved by the fire department. A building permit for a dwelling unit to be located further than five hundred feet from a fire hydrant shall not be issued without the approval of the fire chief. The fire chief may require the installation of additional safety equipment, including fire hydrants or stand pipes, as a condition of such approval.

Shape, materials and style:

The accessory dwelling unit shall be architecturally compatible with the primary dwelling unit, in terms of appearance, materials and finished quality.


Detached ADUs are limited to one story and 16 feet in height, unless located above or below a garage. Roof decks are not permitted on detached ADUs.

Building height shall not exceed fourteen feet if a minimum roof pitch of 3:12 is provided or ten feet if less than a 3:12 roof pitch is provided; Accessory dwelling units constructed above detached garage, pursuant to Section 21.10.030 are not subject to the one-story/fourteen-foot height limitation imposed on accessory structures.

Design review:

A building permit application for an accessory dwelling unit shall be approved ministerial if all conditions are met.

Number of Bedrooms:

Not specified by State Standards.


Owner-occupancy will not be required for new Accessory Dwelling Unit (ADU)s (conversion and new construction) built between 2020 and 2025. ~ SB13 Update

Utility connections:

Description and location of water and sanitary (sewer) services, and no new or separate utility connection shall be required between the accessory dwelling unit and the utility, and no related utility connection fee or capacity charge shall be required, if: Adequate water and sewer capacity and facilities for the accessory dwelling unit must be available or made available. accessory dwelling units shall not be considered new residential uses for the purposes of calculating connection fees or capacity charges for utilities. Any utility connection fee or charge shall be proportionate to the burden of the proposed accessory dwelling unit upon the water or sewer system; and the fee or charge shall not exceed the reasonable cost of providing the service.

Historic Requirements:

Additional review may be required if the location of the proposed accessory dwelling unit is within an architecturally and historically significant historic district.

Coastal Areas:

Ordinance is the implementing ordinance of the Carlsbad Local Coastal Program, and therefore, an amendment to the Zoning Ordinance also constitutes an amendment to the Local Coastal Program.


The accessory dwelling unit has independent exterior access from the primary dwelling.

Allowed Zones:

*** Beginning in 2020, according to state law, all residential zoning districts, including single-family and multi-family, are allowed to build Accessory Dwelling Units. ***

Residential Building Code:

The California Building Code (CBC) 2019 is adopted.

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