What Is Required For An ADU in California?

ADUs in San Gabriel Valley, CA

In California ADU (Accessory Dwelling Unit) requirements mandate that most jurisdictions MUST allow ADUs with a baseline of 800 sq. ft. size, 16 ft. height, and 4 ft. setbacks from property lines, even though local regulations can establish higher standards. Knowing your specific city or county is essential for those reasons. Key requirements include a kitchen, a minimum 150 sq. ft. size for JADUs and ADUs, and compliance with local zoning, lot coverage, and fire/health regulations.  

State vs. Local Regulations 

• State Baseline: State law establishes minimum standards for all localities to follow, ensuring that you can build an ADU with at least 800 square feet, 16 feet in height, and a 4-foot setback from rear and side property lines.
• Local Ordinances: Cities and counties can create their own ordinances that set higher standards or different specifications for ADU size, height, and setbacks, as long as they adhere to state law.

Key Requirements

• Minimum Size: ADUs must be at least 150 square feet, and JADUs also follow this minimum. 
• Kitchen: All ADUs are required to have a kitchen with a cooktop, stove, oven, or range, according to the Sac County Planning Department. 
• Height: Detached ADUs have a state-mandated height limit of 16 feet. Attached ADUs can be higher but are limited by the primary residence's height and local ordinances. 
• Setbacks: A 4-foot setback from the rear and side property lines is a state requirement for detached ADUs, but front yard setbacks are determined by local ordinance. 
• Lot Coverage: Local regulations on lot coverage, which is the percentage of your property covered by structures, can impact ADU size and placement, though some lots can still build an 800 sq. ft. ADU if it would otherwise violate lot coverage rules. 
• Access: ADUs must meet specific requirements for access by fire and emergency vehicles, with the distance varying based on whether the ADU is sprinklered. 

Planning and Permitting

• Check with Local Authorities: To find your specific ADU requirements, consult your city or county planning department's ADU guidelines. 
• Required Documents: You will need to submit a permit application along with detailed plans, including site, floor, structural, and utility plans. 
• Other Approvals: You may also need soil reports, stormwater management plans, and approval from your local fire department and any relevant homeowner's association (HOA). 

Important Considerations

• JADU (Junior Accessory Dwelling Unit): A JADU is a separate, smaller type of ADU, limited to 500 square feet and must be part of the primary dwelling. 
• Unreasonable Restrictions: Local ordinances cannot impose unreasonable restrictions that make it impossible to build an ADU, such as excessive fees or requirements for major structural changes beyond state law. 
• Solar Power: Newly constructed detached ADUs must comply with the state's Energy Code, which may require adding PV modules to an existing solar system on the property. 

We can help you understand how state and local San Gabriel Valley ADU regulations apply to your ADU project. Call San Gabriel Valley ADU Construction Contractors today to learn more.