ADUs & Accessory Dwelling Units in Northern California

California has passed a series of laws that require every city and county to allow ADUs under objective, statewide standards. The most significant change is ministerial review: a compliant ADU application must be approved administratively, without a discretionary hearing, and within a defined timeframe — which removes much of the uncertainty that used to stall these projects. State law also sets baseline allowances for size and setbacks and limits how local rules can restrict them.

Cities and counties can still adopt some local objective standards on top of the state floor, so the exact envelope for your property depends on your jurisdiction. We confirm the applicable rules during feasibility, then submit the plans, respond to plan-check comments, and pull the permit for your city or county.

ADUs take several forms, and the right one depends on your lot, budget, and how you plan to use the space. A detached ADU is a standalone backyard unit that offers the most privacy and flexibility. An attached ADU shares a wall with the main home and can be more efficient to build and connect to utilities. A garage conversion reuses an existing structure — often the fastest, lowest-cost path because the foundation, walls, and roof are already there.

A junior ADU (JADU) is carved out of the existing home, up to a limited size, with its own entrance and a compact kitchen. JADUs are the smallest and often quickest option, though state law allows jurisdictions to require the owner to live on the property when one exists. We walk you through which type fits your parcel, your goals, and the rules that apply.

State law establishes baseline size allowances and reduced setback requirements for ADUs, with a smaller footprint always permitted under the streamlined standards. Garage conversions and attached units follow rules tied to the existing structure. The exact maximum for your property comes down to lot size, unit type, and any local ordinance, which we verify before design so the plan we draw is the plan we can permit.

Utilities are a key part of the plan. Depending on the design and your existing service, we run dedicated or sub-metered electrical, water, sewer, and gas as needed — often new trenching and connections for a detached unit, or a tie-in to existing service for a garage conversion or JADU. Every ADU is designed to California's Title 24 energy code, and we coordinate the inspections along the way.

Homeowners build ADUs for different reasons, and the layout follows the purpose. As a rental, an ADU can generate long-term income that helps offset a mortgage — and under current statewide law, jurisdictions generally cannot impose an owner-occupancy requirement on a standard ADU, which is part of what makes them work as rentals. As a family suite, an ADU keeps aging parents or adult children close with privacy on both sides. Many owners plan for both over time, so we design flexible units that can shift between uses.

If a connected expansion of the main house fits your goals better than a separate unit, compare an ADU with a home addition, or have us manage the whole build as your general contractor.