ADU FAQ

Accessory Dwelling Units (ADU) FAQ

In 2016, the State of California adopted legislation pertaining to Accessory Dwelling Units (ADUs), formerly referred to as Second Dwelling Units. The City updated its zoning ordinance to be consistent with the new State law. In an effort to assist residents with the new standards, Staff has put together a handout to answer frequently asked questions.

Click here to access a PDF handout of this information!

Frequently Asked QuestionsAnswer
What is an ADU?
An ADU is a living unit that provides complete, independent living facilities for one or more persons and includes areas for living, sleeping, eating, cooking and sanitation on the same parcel as the existing single family dwelling unit.
Where are ADUs allowed in Brea? An ADU is permitted in single and multiple family residential zones, on properties where there is one existing single family residence.
Is a permit required for a new ADU?Yes, in all cases a building permit is required. Property owners interested in constructing an ADU on their property are encouraged to talk to Planning Division Staff prior to preparing construction documents, to discuss your concept and verify what permits will be needed.
Can an ADU be sold separately from the primary residence?No.
Can an ADU be rented?Yes. The property owner must live on the property in either the primary residence or the ADU, and the other unit may be rented.
What is the maximum size an ADU can be? An ADU may be up to fifty percent of the existing living area of the primary residence, with a maximum total floor area of 1,200 square feet. In some instances an ADU may exceed the permitted size with the approval of a Certificate of Compatibility.
Can a portion of an existing house, garage or other accessory structure be converted to an ADU? Yes, provided the structure was legally constructed with building permits and the structure can be upgraded to meet the building code requirements for a living unit. When an existing garage or other accessory structure is converted to an ADU, no additional building setback is required. The ADU must have independent exterior access from the existing residence.
Can an ADU be constructed above or attached to a garage? Yes, provided the garage was legally constructed with building permits and the structure can be upgraded to meet the building code requirements for a second story and a living unit. An accessory dwelling unit constructed above or attached to a garage must have a minimum setback of five feet from side and rear property lines.
Is parking required for an ADU? An ADU must provide one parking space. The parking space may be covered or uncovered and can be provided on an existing driveway. If the required parking for primary residence is displaced by ADU and one additional parking space is provided for the ADU, then the replacement parking spaces for the primary residence may be covered, uncovered, tandem, or spaces created by mechanical automobile parking lifts.
Can parking for an ADU be waived? 

Parking for an ADU may be waived in any of the following instances:

a. The ADU is located within one-half mile of public transit, including transit stations and bus stations.

b. The ADU is located within an architecturally and historically significant historic district.

c. The ADU is part of the existing primary residence or an existing accessory structure.

d. When on-street parking permits are required but not offered to the occupants of the ADU.

e. When there is a car share vehicle located within one block of the ADU.



Attached or Detached ADU1ADU created out of existing space2
Permitted Zoning Districts
Allowed in all single family and multifamily zones. Only one ADU may be permitted per lot.Allowed in all single family and multifamily zones. Only one ADU may be permitted per lot.
Building Setbacks
Comply with the minimum standards per underlying zone.

ADU above or attached to a garage - min. 5' from side and rear property lines.
No setback required. Must be sufficient for fire safety.
Building SeparationDetached ADUs –  10’ separation from the existing primary dwellingNo additional distance is required.
Maximum Building HeightComply with standards per underlying zone.Comply with standards per underlying zone.
Lot CoverageComply with standards per underlying zone.Comply with standards per underlying zone.
Maximum Floor Area50% of primary dwelling, up to 1,200 sq. ft.50% of primary dwelling, up to 1,200 sq. ft.
Parking for ADU
1 Parking space required3

No parking required in specific circumstances4
No parking required

If required parking for primary dwelling is displaced by ADU then parking for primary dwelling must be replaced onsite.
Owner Occupancy5RequiredRequired
Entryway
Independent exterior entryway required. Interior entry to the primary dwelling permitted.Independent exterior entryway required.  Interior entry to the primary dwelling permitted.

A full version of the City’s Ordinance No. 1203 and development standards that apply to ADUs can be found on the City’s website at the following link: http://www.ci.brea.ca.us/509/Meeting-Agendas-Minutes


[1] ADU may be attached to the primary dwelling or an existing legally established accessory building.

[2] An existing dwelling or accessory structure, provided that the existing structure was legally established with building permits and can be upgraded to meet building code requirements for a living unit.

[3] When parking is required, the ADU parking space maybe covered or uncovered and must meet all parking space location, dimension, and surfacing requirements. The space may be provided as tandem parking on an existing driveway.

[4] Parking standards for an ADU shall not be required in any of the following instances:

a. The ADU is located within one-half mile of public transit, including transit stations and bus stations.

b. The ADU is located within an architecturally and historically significant historic district.

c. The ADU is part of the existing primary residence or an existing accessory structure.

d. When on-street parking permits are required but not offered to the occupants of the ADU.

e. When there is a car share vehicle located within one block of the ADU.

[5] The occupant of either the primary dwelling or the ADU shall be the owner of both units.