Check your property's zoning, browse designs & get contractor estimates for your ADU project:
Last Updated 09/20/21
City Hint: The City of Garden Grove permitted a total of 379 ADU projects in the past year of 2020.
Number of ADUs allowed:
Only one ADU and/or one JADU can be constructed on a property developed or proposed to be developed with a single-family home. On properties with multi-family developments, up to two detached ADUs are allowed or one or more converted ADUs may be constructed within portions of existing multiple-family dwelling structures that are not used as livable space, up to 25% of the existing multiple-family dwelling units on the lot.
Types of ADUs allowed:
Detached ADU, Attached ADU, Junior ADU are permitted. Accessory Dwelling Unit (ADU)s may be new construction or converted from existing space. Junior Accessort Dwelling Unit (JADU)s must be converted from existing space.
There is no minimum lot size requirement. State law does not impose a minimum lot size.
The maximum size of an ADU with 2 or more bedrooms is 1,200 square feet. The size of a new attached ADU is 1,200 square feet or 50% of the floor area of the primary dwelling unit, whichever is less. If the size of the primary residence is less than 1,600 square feet, the attached ADU may have a total floor area of up to 800 square feet. State law does not limit the number of bedrooms within an ADU. However, there are maximum unit sizes for an ADU. A studio or 1-bedroom ADU shall not exceed 850 square feet in floor area and an ADU with two or more bedrooms shall not exceed 1,200 square feet in floor area.
No setback shall be required for an existing living area or accessory structure or a structure constructed in the same location and to the same dimensions as an existing structure that is converted to an accessory dwelling unit or to a portion of an accessory dwelling unit, and a setback of no more than four feet from the side and rear lot lines shall be required for an accessory dwelling unit that is not converted from an existing structure or a new structure constructed in the same location and to the same dimensions as an existing structure
(I) Parking requirements for accessory dwelling units shall not exceed one parking space per accessory dwelling unit or per bedroom, whichever is less. These spaces may be provided as tandem parking on a driveway.
(II) Off-street parking shall be permitted in setback areas in locations determined by the local agency or through tandem parking, unless specific findings are made that parking in setback areas or tandem parking is not feasible based upon specific site or regional topographical or fire and life safety conditions.
(III) This clause shall not apply to an accessory dwelling unit that is described in subdivision (d).
(xi) When a garage, carport, or covered parking structure is demolished in conjunction with the construction of an accessory dwelling unit or converted to an accessory dwelling unit, the local agency shall not require that those off-street parking spaces be replaced.
Notwithstanding any other law, a local agency, whether or not it has adopted an ordinance governing accessory dwelling units in accordance with subdivision (a), shall not impose parking standards for an accessory dwelling unit in any of the following instances:
(1) The accessory dwelling unit is located within one-half mile walking distance of public transit.
(2) The accessory dwelling unit is located within an architecturally and historically significant historic district.
(3) The accessory dwelling unit is part of the proposed or existing primary residence or an accessory structure.
(4) When on-street parking permits are required but not offered to the occupant of the accessory dwelling unit.
(5) When there is a car share vehicle located within one block of the accessory dwelling unit.
An accessory dwelling unit shall not be required to provide fire sprinklers if they are not required for the primary unit. The ADU shall be setback at a distance sufficient for fire safety.
Shape, materials and style:
The Municipal Code requires the ADU to be compatible in design with the existing home, which includes similar roof type and pitch, exterior finishes, and color.
The height limit of a new ADU is 16 feet, measured from grade to roof ridgeline, which only allows for a single-story ADU.
Applications for development of an accessory dwelling unit must be submitted to the Director on a form prepared by the city and must include all information and materials proscribed by such form. No application shall be accepted unless it is completed as prescribed and is accompanied by payment for all applicable fees. The Director shall ministerially review and approve or disapprove a complete application for an accessory dwelling unit within 120 days of submittal of a complete application. Review is limited to ensure that the accessor y dwelling unit complies with the requirements of this subsection. Any Other that is unable to comply with the development standards and conditions of this subsection shall first apply for and secure the approval of a variance pursuant to the provisions of this code before a ADU may be approved.
Accessory dwelling units shall not be considered new residential uses for the purposes of calculating connection fees or capacity charges for utilities, including water and sewer service.
Number of Bedrooms:
The accessory dwelling unit shall not contain more than two sleeping units.
Owner-occupancy will not be required for new Accessory Dwelling Units (conversion and new construction) built between 2020 and 2025. ~ Updated: State Law SB-13
Accessory dwelling units shall not be considered new residential uses for the purposes of calculating connection fees or capacity charges for utilities, including water and sewer service. Adequate infrastructure, including, but not limited to, sewer and water services and streets sufficient for traffic flow and circulation, shall be available within the residential neighborhood in which an accessory dwelling unit not located within the space of an existing structure is proposed to be located to serve such accessory dwelling unit, as determined by the Public Works Director.
If the accessory dwelling unit is located within an architecturally and historically significant district, additional review may be required.
*** Beginning in 2020, according to state law, all residential zoning districts, including single-family and multi-family, are allowed to build Accessory Dwelling Units. ***
The property shall be zoned for R-1 single-family residential uses.
Residential Building Code:
The California Building Code (CBC) 2019 is adopted.
This estimate is based on recently completed projects in the area and is inclusive of all typical soft costs such as permitting, design and engineering fees.