Check your property's zoning, browse designs & get contractor estimates for your ADU project:
Number of ADUs allowed:
According to state law, all single-family homes are allowed at least one ADU. Additionally, single-family parcels which are owner-occupied may create one ADU and one Junior Accessory Dwelling Unit. Also, multi-family parcels may now add one ADU per every four existing residential units, so long as they were legally established.
Types of ADUs allowed:
Detached ADU, Attached ADU, Junior ADU are permitted. ADUs may be new construction or converted from existing space. JADUs must be converted from existing space.
ADU projects on single family or multi-family residential parcels will not be subject to the minimum lot size of the underlying local zoning code or by special ordinance. ~ AB68 & AB881 Update
Single-family and multi-family Properties will be allowed to construct up to 850 square feet for a one bed ADU or up to 1,000 square feet for a two bed ADU, regardless of the underlying zoning standards of the property. A Junior Accessory Dwelling Unit up to 500 square feet is allowed. The minimum size of any living unit (including Accessory Dwelling Unit (ADU)s and Junior Accessory Dwelling Units) is 150 square feet according to California Residential Code. ~ Updated: State Law AB-68
Setbacks for a detached new construction Accessory Dwelling Unit (ADU) shall be no more than 4 ft. from the rear and side lot lines. No setbacks shall be required for Accessory Dwelling Unit (ADU)s and Junior ADUs converted from legally eastablished existing space. Attached new construction Accessory Dwelling Unit (ADU)s and conversions from existing space to be expanded must comply with the setbacks of the underlying zone. ~ AB68
Replacement parking shall not apply to lots which convert an existing garage to an Accessory Dwelling Unit or Junior Accessort Dwelling Unit (JADU). ~ AB68 & AB881 Update
Accessory dwelling units shall not be required to provide fire sprinklers unless they are also required for the primary dwelling. ~ State Standards
Shape, materials and style:
Specific design styles and restrictions are not specified under State Standards. Passageways shall not be required in conjunction with the construction of an accessory dwelling unit. ~ State Standards
The maximum height of an ADU is not specified in the state standards. If ADU maximum height is not established locally, the height limitations of the underlying zone shall apply. ~ State Standards
The municipality shall provide a ministerial review process which is not based on a discretionary approval for an ADU. The process shall take no less than 120 days. Valid applications submitted for ADUs, if not approved or denied within 120 days from submission, shall be considered approved. ~ State Standards
Number of Bedrooms:
No maximum number of bedrooms is established other than that implied by the maximum size of an ADU allowed. ~ State Standards
Owner-occupancy will not be required for new Accessory Dwelling Units (conversion and new construction) built between 2020 and 2025. ~ SB13 Update
Connection and utility fees shall be reasonable, and shall not be disproportionately higher than those to develop primary dwellings, so as not to deter the development of ADUs. If a private sewage disposal system is used, such as a septic system, review and approval by a local health officer may be required. ~ State Standards
*** 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.
ADU Design Library
Browse hundreds of models to find the right fit for your property.
ADU Model 560 sqft
28 ft x 20 ft
ADU Model 752 sqft
33 ft x 25 ft
ADU Model 504 sqft
24 ft x 21 ft
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.