Garage Conversion & ADU in San Ramon, CA: Rules, Cost and Process (2026)

Short answer: yes, you can convert a garage into an ADU in San Ramon. California law makes ADU permits ministerial (no public hearing), requires the city to act within 60 days, and does not require replacement parking when you convert a garage. Green Living Remodeling handles the plans, the permit at the San Ramon Permit Center and the construction, and quotes every project individually after a free on-site visit.

What San Ramon and California allow (2026)

One ADU and one Junior ADU (JADU) are allowed on most single-family lots in San Ramon, in line with state law.
Size: a detached ADU may be up to 1,200 sq ft; an attached ADU up to 50% of the main home or 1,200 sq ft, whichever is less; a JADU is up to 500 sq ft inside the existing home.
Garage conversions: converting an existing, legally built garage is exempt from the 4-foot side and rear setback rule and does not require replacement parking.
Timeline: the city has 60 days to approve or deny a complete ADU application, and the review is objective — if the plans meet the standards, the permit is issued.
Energy code: permits pulled on or after January 1, 2026 fall under the 2025 Title 24 energy standards, so insulation, windows, ventilation and water heating in the new unit must meet current requirements.

Rules change and every lot is different (HOA covenants in communities like Gale Ranch, Windemere or The Bridges can add their own review). We confirm the details for your address before you spend a dollar on plans.

What a garage-to-ADU conversion includes

Scope item	Why it matters
Insulated walls, ceiling and slab treatment	Garages are unconditioned; the unit must meet Title 24 envelope requirements.
Bathroom and kitchenette plumbing	New drain and supply lines, often trenching through the slab, plus a water heater (tankless is common).
Electrical service and sub-panel	Many homes need a panel upgrade to add a kitchen, HVAC and laundry circuits.
Heating and cooling	A heat-pump mini-split is the usual code-friendly choice.
Windows, egress and a separate entrance	Bedroom egress, natural light and ventilation are required.
Fire and life safety	Smoke and CO detectors, and fire separation between the ADU and the main house where required.
Finishes	Flooring, drywall, cabinets, fixtures and exterior work where the garage door was.

How much does a garage conversion cost in the East Bay?

Published 2026 Bay Area guides put most garage-to-ADU conversions from roughly $80,000 upward, with the total driven by plumbing runs, electrical service, HVAC, window changes and the level of finish. A detached new-build ADU costs considerably more than converting the existing structure. Because the biggest variables are hidden in your slab, panel and roof, we quote only after seeing the garage in person — the estimate is free and includes the permit path.

Our process

Free site visit in San Ramon, Danville, Dublin or Pleasanton: we check the slab, framing, panel, plumbing and access, and talk through layout and budget.
Design and plans that meet San Ramon’s objective standards and Title 24.
Permit through the City of San Ramon Permit Center (7000 Bollinger Canyon Rd; (925) 973-2580).
Construction by our own crew, with inspections scheduled at each stage.
Final inspection and hand-over, with a 1-year workmanship warranty.

Frequently asked questions

Do I lose my parking if I convert the garage?

Under California ADU law, no replacement parking is required when a garage is converted to an ADU, so you may keep the driveway as your parking.

Can I rent the ADU?

ADUs may be rented; check the current rules on rental terms and any HOA restrictions for your community before planning income.

How long does the whole project take?

Plan on a few weeks for design and up to 60 days for the permit decision, then construction, which typically runs a few months depending on scope and inspections.

Is a room addition better than a conversion?

If you need the garage for storage or cars, a room addition or second-story addition may fit better. We build both and can compare the two on your lot.

Will the new unit have to meet the 2025 energy code?

Yes. Permits filed on or after January 1, 2026 must comply with the 2025 Title 24 standards. See our Title 24 guide for remodels.

Get a free garage-conversion estimate or call (510) 725-4073.

Sources: California HCD ADU guidance and San Ramon Zoning Ordinance ADU standards (2026); California Energy Commission, 2025 Building Energy Efficiency Standards (effective January 1, 2026). Information is general and not legal advice; requirements are confirmed per address during the free site visit.