Can You Build an ADU Before the Main House in California?

ADUs can generate passive rental income that helps offset future mortgage costs and fund future construction. If you live in the ADU while the main house is being built, you can avoid costly temporary housing and be onsite to monitor progress. Additionally, securing financing for an ADU is often easier, which increases your property value immediately and gives you leverage for a bigger loan.

Starting with an ADU streamlines the overall building process. With critical infrastructure already in place, transitioning to the primary residence construction becomes smoother and more cost-effective. In addition, since we handle things like site preparation and utility connections, we reduce delays when it’s time to build the main house.

Providing access, landscaping, and privacy while considering future utility expansions requires careful ADU planning. Consider that the ADU could later serve as a guesthouse, office, or rental, so thoughtful design is essential for long-term value. Moreover, choosing complementary styles and materials prevents a disjointed look after the main house goes up.

Getting your property infrastructure and utilities ready for an ADU can be time-consuming and expensive. You also should consider the following:

• Permits: Some cities may require additional approvals when building an ADU in California before a main house.
• Zoning: Local ordinances vary, and some jurisdictions restrict ADU-only lots or impose stricter setback and size requirements.
• Financing: You may need to explore alternative funding instead of a traditional mortgage.

Furthermore, if you plan to sell the property, buyers may hesitate to purchase an ADU-only property.

California implemented laws in 2016 and 2019 regarding ADU construction that significantly ease the process of adding one to your property:

• SB 1069: Eliminates discretionary approval processes, reduces parking requirements, and limits utility connection fees.
• AB 2299: Mandates local ordinances permitting ADUs in single and multifamily zones.
• SB 13: Prohibits owner-occupancy requirements for ADUs and reduces impact fees.
• AB 68: Requires municipalities to approve ADU applications within 60 days.
• AB 881: Limits local government construction restrictions and eliminates parking requirements when near public transit.

Additionally, Senate Bill 9, known as the California Housing Opportunity and More Efficiency Act, allows property owners to subdivide single-family lots and build up to four ADUs. Additional policies, such as SB 10, enable local governments to rezone parcels for up to 10 units near transit-rich areas.

However, this recent legislation primarily addresses scenarios where a main residence already exists and may not directly apply to building an ADU before the main house. We understand this distinction and work diligently to make sure that your ADU-first project complies with all applicable state and local regulations.