Check your property's zoning, browse designs & get contractor estimates for your ADU project:
City Hint: The City of Placentia permitted a total of 16 ADU projects in the past year of 2020.
Number of ADUs allowed:
According to state law, all single-family homes are allowed at least one ADU. Additionally, single-family lots which are owner-occupied may create one ADU and one Junior Accessory Dwelling Unit. Also, multi-family lots 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.
Single family and multi-family residential lots will not be subject to the minimum lot size of the underlying zoning district or by ordinance for Accessory Dwelling Unit (ADU) projects. ~ AB-68
Single-family and multi-family Properties will be approved to add up to 850 sq.ft. for a one bedroom ADU or up to 1,000 sq.ft. for a two bedroom ADU, regardless of the underlying zoning standards of the property. A Junior Accessort Dwelling Unit (JADU) up to 500 sq.ft. is approved. The minimum size of any living unit (including Accessory Dwelling Unit (ADU)s and Junior Accessort Dwelling Unit (JADU)s) is 150 sq.ft. according to California Residential Code. ~ Updated: State Law AB-68
Newly constructed detached Accessory Dwelling Units can be as close as 4 feet from the rear and side property lines. Setbacks will not be required for Accessory Dwelling Units and Junior ADUs converted from existing space that was legally eastablished. Attached Accessory Dwelling Units and conversions from existing space to be expanded will be required to comply with the setbacks of the underlying zone. ~ AB68 & AB881 Update
Parcels which convert an existing garage to an Accessory Dwelling Unit or JADU will not be subject to replacement parking requirements. ~ Updated: State Law AB-68
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
Between between 2020 and 2025, owner occupancy requirements will not apply to new Accessory Dwelling Unit (ADU)s. (applicable to new construction and conversion units) ~ SB13
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 200 sqft
20 ft x 10 ft
ADU Model 600 sqft
30 ft x 20 ft
ADU Model 896 sqft
52 ft x 22 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.