Two Detached ADUs in Milpitas (AB 956, 2027)
Plan Two ADUs in Milpitas: Free Site Assessment
Milpitas ADU rules today (2026)
From January 1, 2027, state law (AB 956) requires cities, including Milpitas, to approve up to two detached ADUs on a lot with a single-family home. Milpitas supports ADUs with a pre-approved plan program, free “ADU Mondays” consultations and a legalization program. Here is how the new law and the current local ADU rules fit together.
- Units allowed now: the city’s ADU code (Municipal Code Sec. XI-10-13.08) allows one ADU plus one JADU on a single-family lot.
- Detached ADU size: the city’s ADU code allows 850 sq ft for a studio or one bedroom and 1,000 sq ft for two bedrooms, and up to 1,200 sq ft in the hillside area. The city’s pre-approved program page says a Minor Site Development Permit is needed if the building is over 800 sq ft.
- Attached ADU and JADU: an attached ADU can be 50% of the main home, but never less than 800 sq ft with 4 ft setbacks. A JADU can be up to 500 sq ft.
- Height: the city’s ADU code allows 16 ft for a detached ADU, 18 ft near transit or on multifamily lots, and up to 2 ft more for roof pitch. Attached ADUs can reach 25 ft.
- Setbacks: 4 ft side and rear, and at least 6 ft from the main home’s rear wall.
- Fire separation: a detached ADU less than 10 ft from the main home needs a 1-hour wall and 45-minute openings.
- Process: by-right review with a 60-day decision clock, submitted through the city’s Online Submittal System.
- Pre-approved plans: the city lists a 499 sq ft one-bedroom, one-bath plan, and plan review is up to 50% faster. We confirm each plan is valid under the 2025 codes.
What changes on January 1, 2027
AB 956 requires Milpitas 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.
Milpitas allows one ADU plus a JADU on a single-family lot today. AB 956 raises the detached count to two. The city’s by-right threshold around 800 sq ft already lines up with the size the city may set for each of two units, and its 499 sq ft pre-approved plan fits well within it. The 10 ft fire-separation rule will matter when two units and the main home share one backyard. Milpitas will need to update its ordinance, and we confirm current rules as it does.
Recent Axiom work
Professional photos from a recent Axiom Renovation full remodel and addition in Los Gatos.
Planning two detached ADUs on a Milpitas lot
- Hillside area: lots in the Hillside Building Code area cannot use pre-approved plans and have their own size rules.
- Flood zones: pre-approved plans are not available in the Special Flood Hazard Area unless the plan has a flood option.
- Spacing: keeping each ADU 10 ft or more from the main home avoids rated walls and openings; closer units need fire-rated construction.
- Easements: ADUs cannot sit in an easement, which can limit where a second unit goes.
- Electrical: two units plus the main home usually need a load calculation and often a service upgrade.
Building ADUs in Milpitas with Axiom
Axiom Renovation designs, permits and builds ADUs in Milpitas. Read our Milpitas ADU guide, see our Milpitas service area, or start with the AB 956 overview. Neighbors can read the guides for Fremont and San Jose.
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.
Milpitas Two-ADU FAQ
Can I build two detached ADUs in Milpitas?
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. Today Milpitas allows one ADU plus one JADU.
How large can each ADU be in Milpitas?
The city’s ADU code allows a detached ADU of 850 sq ft with one bedroom or 1,000 sq ft with two, and a Minor Site Development Permit applies over 800 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 Milpitas?
The city’s ADU code allows 16 ft for a detached ADU, 18 ft near transit or on multifamily lots, and up to 2 ft more for roof pitch.
How close can an ADU be to my house in Milpitas?
A detached ADU must be at least 6 ft from the main home’s rear wall. If it is less than 10 ft away, it needs a 1-hour fire-rated wall and 45-minute rated openings.
Can I use a pre-approved ADU plan in Milpitas?
Yes, on eligible lots. The city lists a 499 sq ft one-bedroom plan, with plan review up to 50% faster. Hillside lots, most flood-zone lots and sites with easement conflicts are not eligible.
Who builds two-ADU projects in Milpitas?
Axiom Renovation designs, permits and builds ADUs in Milpitas 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.