Maybe you’re planning a home for an aging parent. Maybe your adult children need a place of their own, or you’re considering a rental to help support your household. Whatever brings you to the conversation, an accessory dwelling unit (ADU) starts with the people who will live there.

California’s newly signed AB 956 could give qualifying homeowners another option: two detached ADUs on the same property. A companion law, SB 1117, changes how certain ADU impact fees are calculated. Both were signed September 29, 2026, and take effect January 1, 2027.

Here’s what these changes could mean as you start planning.

Can you build two detached ADUs in California?

Starting January 1, 2027, AB 956 expands the state’s ministerial approval pathway to two detached, newly constructed ADUs on qualifying lots with an existing or proposed single-family home in a residential or mixed-use zone.

“Ministerial approval” means the permitting agency checks the plans against applicable requirements without a discretionary approval process. You still need permits and plans that meet the required standards.

Under this pathway, local agencies may limit each ADU to 800 square feet of livable space and apply the state-authorized height limits. Required side and rear setbacks cannot exceed four feet. The law also does not require ministerial approval of a junior accessory dwelling unit (JADU) on a lot where two detached ADUs have been constructed under this provision.

Your property’s existing homes, available space, and site conditions will help determine what can be approved. Check with your local city or county for the most recent permitting requirements.

Read AB 956 on California Legislative Information HERE.

More room for family, with space of their own

For some families, two ADUs could mean keeping an aging parent and an adult child close by while giving each their own home. Others may want one ADU for family and another for a long-term rental.

As you consider the possibilities, think about how the homes would work together. Where would each entrance face? How much privacy would everyone have? Would a one-bedroom layout meet their needs, or would a second bedroom be useful?

These are the conversations we like to have before you settle on a floor plan.

The Pasadena: Two Bedrooms and More Flexibility

With two bedrooms, one bathroom, and approximately 744 square feet, the Pasadena offers more sleeping space for adult children, a small family, or a long-term tenant.



The Piedmont: One Bedroom, Room for Independent Living

The Piedmont features one bedroom, one bathroom, and approximately 516 square feet, offering an independent home for a parent, an adult child, or a long-term tenant.

Whether you’re considering two of the same model or different layouts, the plans and property will need to be reviewed to determine what can be permitted. Model dimensions are approximate, and the livable-space measurements used for permitting and fees should be confirmed during planning.

Start with What’s Possible on Your Property

Before choosing one ADU or planning for two, check with your local city or county planning and building department for the most recent ADU permitting requirements and guidance on the changes taking effect in 2027.

Your property review should consider setbacks, height, utilities or septic capacity, easements, building and fire safety, and any applicable coastal requirements. For a prefab home, delivery access and foundation planning matter too.

The California Department of Housing and Community Development’s ADU resources provide statewide guidance. Check the dates on handbooks and local checklists, since older materials may not yet reflect the new laws.