Garage-to-ADU Conversion INDEPENDENT UTILITIES · CAN BE LARGER OR DETACHED · RENTAL-READY

A full second home, built out of the garage you're not using.

An Accessory Dwelling Unit (ADU) is a complete, independent living space — its own kitchen, bathroom, entrance and utility connections — and California's state ADU law generally overrides local ordinances that would otherwise block it. Converting an existing attached or detached garage into an ADU is usually the most cost-effective way to add one, since the structure, slab and roofline are often already there.

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What Makes an ADU Different From a JADU

Independent utilities and no owner-occupancy requirement — but a bigger scope.

Unlike a JADU, an ADU requires its own independent electrical, water and sewer connections, which typically means a new utility meter or sub-meter and more extensive rough-in work. In exchange, an ADU isn't capped at 500 square feet — state law generally allows up to 1,200 square feet depending on your lot and local ordinance — and there's no requirement that you live on the property, which means an ADU can be a straightforward rental unit in a way a JADU generally can't. For an attached garage, that usually means routing new electrical and plumbing runs from the main service; for a detached garage, it means running new utility lines from the street or main house across the yard, which is where site conditions start to matter more than they do with a JADU.

Garage converted into a fully independent ADU with new entrance and windows

What's Included

Everything needed to take your garage from storage space to a permitted ADU.

Structural & Utility Feasibility Assessment

We evaluate your garage's slab, framing and roofline, plus how far new electrical, water and sewer lines will need to run to reach it.

Full Kitchen & Bathroom Design

Unlike a JADU's efficiency-kitchen minimum, an ADU gets a full kitchen and bathroom layout designed for independent, long-term living.

Independent Utility Connections

New electrical sub-panel or service, water line, and sewer or septic connection sized for full-time occupancy — coordinated with your city's utility requirements.

Attached or Detached Scope

Whether your garage is attached to the main house or a standalone structure in the backyard, we scope the conversion differently to match the access and utility-routing challenges each presents.

Permit Package & Plan Check

We prepare the ADU permit application and manage plan check corrections with your city, without the owner-occupancy affidavit a JADU requires.

Why It Matters

The biggest ADU cost driver isn't the room — it's the utility run.

Homeowners are often surprised that the finish work on an ADU costs less than expected, while the utility trenching and electrical service upgrade cost more — especially for a detached garage on the far side of a lot. We scope the utility routing as part of the initial feasibility review, not as a change order discovered mid-construction, so your quote reflects what the project will actually take.

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Service Areas

Also converting garages nearby.

Based in San Jose, working throughout Santa Clara, San Mateo and southern Alameda counties.

Atherton Belmont Campbell Cupertino Dublin East Palo Alto Foster City Fremont Gilroy Hayward Hollister Los Altos Los Altos Hills Los Gatos Menlo Park Milpitas Morgan Hill Mountain View Newark Palo Alto Pleasanton Redwood City San Carlos San Jose San Mateo Santa Clara Saratoga Sunnyvale Union City Woodside

FAQ

Questions homeowners ask us

Generally no — California's state ADU law significantly limits what local ordinances can restrict, including minimum lot size requirements and outright bans in most residential zones. Cities can still apply setback, height and design-review rules, which we confirm against your specific address.

State law generally allows ADUs up to 1,200 square feet, though your specific lot size, existing structures and local ordinance may set a different practical limit. Converting an existing garage often lands well under that cap simply based on the garage's existing footprint, unless you're adding square footage.

Often yes, particularly for a detached garage or if your existing electrical service doesn't have capacity for the ADU's added load. We evaluate your panel's existing capacity during feasibility review and scope any upgrade or sub-panel as part of the project.

This depends heavily on your specific city's short-term rental ordinance, which is separate from state ADU law and varies significantly across the South Bay and Peninsula. We can tell you what applies to your address, but recommend confirming directly with your city's planning department before committing to a rental strategy.

Usually, yes — reusing an existing slab, framing and roofline where they're structurally sound avoids a significant portion of new-construction cost. That said, if your garage's structure doesn't meet current code for habitable space, some of that savings narrows. We evaluate this specifically during our feasibility review rather than assuming it either way.

Free, No-Obligation Quote

Let's talk about your garage.

Tell us what you're converting it into — a JADU, an ADU, an office — and we'll get back to you with next steps, usually within one business day.

(408) 442-9136