ADU Builder in Gilroy, CA
Get a Free Gilroy ADU Consultation
Gilroy ADU Rules (Zoning ยง30.54)
- Detached: up to 1,000 sq ft; 16 feet tall, 18 feet near transit, and up to 24 feet when built above a detached garage.
- Attached: up to 50% of the main house, with 850 sq ft for one bedroom or 1,000 sq ft for two or more always allowed; up to 25 feet.
- Junior ADU: up to 500 sq ft.
- Setbacks: 4 feet side and rear; no ADU in the front setback unless it is needed to fit an 800 sq ft unit; conversions need no extra setback.
- Parking: one space for a new ADU, with state exemptions such as transit, conversions, historic districts and car share; no replacement for garage conversions; none for a JADU.
- Design: compatible with the main house in materials, colors and roof.
- No separate sale and no rentals under 30 days. Ministerial approval within 60 days.
ADU Construction
Two Gilroy-Specific Requirements
- Habitat Agency: Gilroy ADU permits require a Santa Clara Valley Habitat Agency “Nitrogen Deposition Only” application.
- Deed restriction: recorded as part of the ADU permit.
- Sewer billing: a detached ADU moves the property’s sewer billing to the multifamily charge.
- School fees: paid before issuance for ADUs over 500 sq ft.
Pre-Approved ADUs in 15 Working Days
Gilroy’s pre-approved ADU program, with a gallery at cityofgilroy.aduaccelerator.org, applies in R1 and R2 zones; hillside and wildland-urban interface parcels are excluded. A complete submittal can be permitted in 15 working days. Apply in GO Permit as “R – Pre-Approved Accessory Dwelling Unit.”
7351 Rosanna Street, Gilroy, CA 95020
Building (408) 846-0451 · Planning (408) 846-0440, Pl**************@**********oy.org
Counter Monday to Thursday, 8:30 a.m. to 4:30 p.m. Applications go through the GO Permit (Gilroy Online Permit) Portal. Plans must be digital, submitted as one bookmarked PDF; paper sets are not accepted.
Inspections are booked in the GO Permit Portal, and the City notes appointments are scheduled about 72 hours out. Inspections are required before concealed work is covered, permits expire after 365 days without an inspection, and a final inspection is required. Contractors need a City of Gilroy business license as well as a state license.
Explore More
Other Gilroy services: Bathrooms · Kitchens · Additions · New Homes · Gilroy overview
Same service nearby: Morgan Hill · San Martin
Gilroy ADU FAQ
How big can an ADU be in Gilroy?
A detached ADU can be up to 1,000 sq ft. An attached ADU can be up to 50% of the house, with 850 or 1,000 sq ft always allowed.
What is the Habitat Agency application?
Gilroy ADU permits require a Santa Clara Valley Habitat Agency Nitrogen Deposition Only application.
How fast is a pre-approved ADU permit?
A complete pre-approved submittal can be permitted in 15 working days in R1 and R2 zones.
Does a detached ADU change my sewer bill?
Yes, it moves the property to the multifamily sewer charge.