Two Detached ADUs in Gilroy (AB 956, 2027)
Plan Two ADUs in Gilroy: Free Site Assessment
Gilroy ADU rules today (2026)
From January 1, 2027, state law (AB 956) requires cities, including Gilroy, to approve up to two detached ADUs on a lot with a single-family home. Gilroy issues pre-approved ADU permits within 15 working days and posts its permit steps online, which helps owners plan a larger project. Here is how the new law and the current local ADU rules fit together.
- Units allowed now: the ADU information sheet on the city’s website (rev. November 21, 2023) allows one ADU (attached, detached or conversion) per single-family home, plus one JADU inside the home. ADU rules are in Zoning Code Article 30.54.
- Detached ADU size: up to 1,000 sq ft. An attached ADU can be 50% of the main home, with exceptions to allow 850 sq ft (one bedroom) or 1,000 sq ft (two or more). A JADU can be up to 500 sq ft.
- Height: 16 ft for a detached ADU, or 18 ft within half a mile of a major transit stop. A unit above a detached garage may reach 24 ft. Attached ADUs can be 25 ft.
- Setbacks: 4 ft side and rear. The front setback applies unless needed to fit an 800 sq ft unit.
- Parking: one space with state exemptions. None for a JADU.
- Process: applications go through the city’s online GO Permit system. Regular ADU permits are typically issued within 30 calendar days of a complete application.
- Pre-approved plans: designs in the city’s ADU Accelerator gallery are permitted within 15 working days. They are limited to R1 and R2 zones.
State review of Gilroy's ADU rules
On April 25, 2023, HCD sent Gilroy findings on its ADU ordinance (Ord. No. 2020-03). Among its 14 findings: the city allowed only one ADU per lot and must allow an ADU, a JADU and an 800 sq ft detached unit together; the 16 ft height limit needed updating to the 18 and 25 ft state limits; front-yard rules cannot block an 800 sq ft unit; standards must be objective, and “compatible” design language was a concern. Where local rules are stricter than state law, state law applies.
Recent Axiom work
Professional photos from a recent Axiom Renovation full remodel and addition in Los Gatos.
What changes on January 1, 2027
AB 956 requires Gilroy to approve up to two detached, new-construction ADUs on a lot with a single-family home. Each of the two may be limited to 800 sq ft of living space, local height limits can still apply, and side and rear setbacks can be no more than 4 ft. Where two detached ADUs are built, a JADU on the same lot does not have to be approved. Owners in HOAs also gain protections.
Gilroy’s information sheet still describes one ADU plus a JADU, and HCD has already told the city to allow more. The city’s 1,000 sq ft detached limit is above the 800 sq ft cap it may set for each of two units. Gilroy’s ADU page includes an HOA approval letter form, so owners in associations should note the HOA protections in state law. Gilroy will need to update its ordinance, and we confirm current rules as it does.
Planning two detached ADUs on a Gilroy lot
- Habitat Plan: the information sheet requires a Santa Clara Valley Habitat Agency Nitrogen Deposition Only application with the building permit.
- Deed restriction: a recorded deed restriction is required, and rentals under 30 days are not allowed.
- Sprinklers: an ADU needs sprinklers only if they are required for the main home.
- Hillside and WUI areas: these lots cannot use pre-approved plans. Pre-approved projects also need a Detached ADU Grading Permit Waiver Request.
- Utilities: ADUs need utility connections, and two units usually need an electrical load calculation and often a service upgrade.
Building ADUs in Gilroy with Axiom
Axiom Renovation designs, permits and builds ADUs in Gilroy. Read our Gilroy ADU builder page, see our Gilroy service area, or start with the AB 956 overview. Neighbors can read the guides for San Martin and Morgan Hill.
Process
Our ADU Process
Step 1
Initial Consultation
We begin with a thorough initial consultation to understand your needs, assess your space, and discuss your vision, budget, and timeline.
Step 2
Planning and Design
At Axiom Renovation, we understand that the planning and design phase of an ADU project is crucial to its success. Our dedicated project managers will work closely with you to understand your goals, design ideas and budget for the project.
Step 3
Material Selection
We guide you through selecting high-quality materials that fit your design and budget, ensuring durability and aesthetic appeal.
Step 4
Demolition and Preparation
Careful demolition and preparation work are performed to ready the space for construction, minimizing disruptions and ensuring a clean work environment.
Step 5
Construction and Installation
Our skilled craftsmen handle the construction phase, including obtaining permits, scheduling appointments, and the actual construction and installation with precision, building the new space according to the approved design.
Step 6
Electrical and Plumbing Work
Licensed professionals conduct all electrical and plumbing work, ensuring everything is up to code and seamlessly integrated into the new ADU.
Step 7
Painting and Finishing
We pay close attention to detail during the painting and finishing stage, ensuring all surfaces are properly prepared and beautifully finished.
Step 8
Fixture and Appliance Installation
We expertly install all fixtures and appliances, ensuring they function correctly and fit perfectly with the overall design.
Step 9
Final Touches and Clean-Up
Final touches are added, and a thorough clean-up is performed, leaving your new space pristine and ready for use.
Step 10
Final Walkthrough and Client Satisfaction
We conduct a final walkthrough with you to ensure every detail meets your expectations and address any remaining concerns, ensuring your complete satisfaction.
Gilroy Two-ADU FAQ
Can I build two detached ADUs in Gilroy?
From January 1, 2027, AB 956 requires the city to approve up to two detached, new-construction ADUs on a lot with a single-family home, if the project meets objective standards. Gilroy’s current information sheet describes one ADU plus one JADU.
How large can each ADU be in Gilroy?
Gilroy’s information sheet allows a detached ADU of up to 1,000 sq ft. Under AB 956, the city may limit each of two detached ADUs to 800 sq ft of living space.
How tall can a detached ADU be in Gilroy?
The information sheet lists 16 ft, or 18 ft within half a mile of a major transit stop, and 24 ft for a unit above a detached garage. HCD told Gilroy in 2023 to update its height rules to the state limits.
How long does an ADU permit take in Gilroy?
Regular ADU permits are typically issued within 30 calendar days of a complete application. Pre-approved plans are permitted within 15 working days.
What extra paperwork does a Gilroy ADU need?
Gilroy asks for a recorded deed restriction and a Santa Clara Valley Habitat Agency Nitrogen Deposition Only application with the building permit.
Who builds two-ADU projects in Gilroy?
Axiom Renovation designs, permits and builds ADUs in Gilroy and is planning two-unit projects for 2027. Call 408-702-2022, Monday to Friday, 9 am to 5 pm.
Sources: AB 956 (Quirk-Silva), signed September 29, 2026, effective January 1, 2027, as summarized by Brownstein Hyatt Farber Schreck and California YIMBY. This page is general information, not legal advice. Local rules change; we confirm current requirements with the city for every project.