ADU Permits in Gilroy: The 2026 Process, Fees, and Timeline

Gilroy runs one of the fastest ADU permit paths in the region, with a catch worth knowing up front. The speed: with a pre-approved plan set and complete documents, the city can issue ADU permits in about 15 working days. The catch: Gilroy’s ADU article (City Code 30.54) caps detached ADUs at 1,000 square feet, stricter than the state’s 1,200 square foot default.

The short version: Gilroy approves ADUs ministerially within 60 days of a complete application, and pre-approved plans can compress that to roughly 15 working days. Detached units max out at 1,000 square feet. Parking is one space with wide exemptions, and it can even sit in your front setback or driveway. We manage the whole permit, with a permitting budget built into one project price.

The Gilroy ADU permit process, step by step

1. Size your project to the local cap. A detached ADU may not exceed 1,000 square feet in Gilroy. Attached ADUs are capped at 50% of the main home’s floor area, though 850 square feet for a one-bedroom or 1,000 square feet for two or more bedrooms is always allowed. Verify your numbers in our Can I build? rules lookup.
2. Design within the height and setback rules. New construction needs 4 foot side and rear setbacks. Detached ADUs are one story and 16 feet, or 18 feet within a half mile of a major transit stop (up to 20 feet to match the main home’s roof pitch), and a unit above a detached garage may reach 24 feet.
3. Plan the parking spot. One space, and Gilroy is flexible about where: the front setback, tandem, or the driveway all work. The requirement is waived for conversions, lots within a half mile walking distance of public transit, historic districts, or a car-share within a block.
4. Choose standard or custom plans. Gilroy pre-approves standardized construction plans, and that route is where the roughly 15 working day permit lives. Custom plans follow the standard 60-day ministerial clock.
5. Submit, plan check, permit, inspections. Ministerial review with no hearing, then foundation, utility, and final inspections. Before the permit issues, the city records a deed restriction confirming the ADU will not be rented for periods under 30 days.

Choose a factory build with us and all of this is handled: plans, submission, corrections, inspections, and a permitting budget built into one project price. Your exact fees are confirmed in your feasibility study.

Designing under the 1,000 square foot cap

The cap sounds limiting until you look at what fits under it. Twelve of our 14 models are 1,000 square feet or less, including every one of our one- and two-bedroom layouts: the 450 square foot studio at $199,000, the 660 square foot Six Sixty at $309,000, the 749 square foot two-bedroom at $369,000, and all four 945 square foot configurations, up to the three-bedroom, two-bath at $479,000, all-inclusive of construction. The only homes the cap rules out are our 1,200 square foot three-bedrooms.

Bonus: our models at 749 square feet and below also duck under the state’s 750 square foot impact-fee waiver, which pairs nicely with Gilroy’s own fee posture, because the city applies no charges to ADUs beyond generally applicable building permit fees plus utility connection and capacity charges as limited by state law.

For the wider county picture, see our Santa Clara County ADU regulations guide.

How long the permit takes

Two speeds. Pre-approved plans with complete documents: about 15 working days, among the fastest in our service area. Custom plans: the standard 60-day ministerial window from a complete application. Either way, site conditions and utilities can add time, and no one outside city hall sets review speed, so never let anyone promise you a hard delivery date off the permit alone.

While Gilroy reviews, your home is being built about 97% complete in our Salinas factory, roughly 35 minutes away, so permit time and build time overlap instead of stacking. The week-by-week version is in our Gilroy ADU timeline guide.

Frequently asked questions

How big can a detached ADU be in Gilroy?

1,000 square feet, by City Code 30.54. That is stricter than the state’s 1,200 square foot default but still fits two- and three-bedroom layouts comfortably, including all four of our 945 square foot configurations.

How fast can I really get a Gilroy ADU permit?

With a pre-approved plan set and complete documents, the city can issue permits in about 15 working days. Custom designs follow the normal 60-day clock. Complete paperwork is the variable you control; city workload is the one you do not.

Where can the parking space go?

In the front setback, tandem, or on the driveway. And many lots skip parking entirely: conversions, lots within a half mile of transit, historic districts, and lots near a car-share are all exempt.

Can I use my Gilroy ADU as a short-term rental?

No. A deed restriction recorded before permit issuance prohibits rentals under 30 days. Long-term tenants and family housing are the plan; our rental income guide shows what that earns.

Get your Gilroy numbers, free

Whether your lot qualifies for the fast lane comes down to your parcel and your plan choice. Book a free property analysis and our team will check your setbacks, transit distance, and model fit. It takes about 30 minutes and costs nothing.