Two Detached ADUs in Menlo Park (AB 956, 2027)
Plan Two ADUs in Menlo Park: Free Site Assessment
Menlo Park ADU rules today (2026)
From January 1, 2027, state law (AB 956) requires the City of Menlo Park to approve up to two detached ADUs on a lot with a single-family home. Menlo Park rewrote its ADU ordinance in 2026, and the new rules took effect on July 10, 2026. Here is how the new state law and the city’s current rules fit together.
The city adopted a new ADU ordinance on June 9, 2026, replacing Zoning Chapter 16.79. The points below follow the version introduced in May 2026; the final text may differ slightly.
- Units allowed now: up to three state-standard units: one ADU inside the house, one JADU and one detached ADU.
- Detached size: 800 sq ft of livable space for a state-standard detached unit. A local-standards unit may be 850 sq ft (one bedroom or less) or 1,000 sq ft (more bedrooms). An attached ADU is capped at 50% of the house.
- JADU: 150 to 500 sq ft, plus up to 150 sq ft for entry and exit.
- Height: 16 ft detached, or 18 ft within a half mile of transit, plus 2 ft for a matching roof pitch.
- Setbacks: 4 ft side and rear. Stairs and landings stay at least 4 ft from lot lines.
- Process: ministerial building permit. Completeness is checked within 15 business days and a decision made within 60 days, or the permit is deemed approved.
- Preapproved ADUs: designers can get plans approved in advance; the owner then files a site-specific building permit.
State review of Menlo Park's ADU rules
In December 2025, the state housing department (HCD) sent a technical-assistance letter noting that the old ordinance may not match state law. On June 15, 2026, HCD found the new ordinance “in substantial compliance with State ADU law.” 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 the city to approve up to two detached new-construction ADUs on a single-family lot. The city may cap each at 800 sq ft of living space and apply height limits; side and rear setbacks can be no more than 4 ft. Where two detached ADUs are built, a JADU need not be approved, and HOA rules cannot block or unreasonably restrict the units. Menlo Park already sets 800 sq ft as the size for its state-standard detached unit, so the two-unit option fits that size. What changes is the count: today one detached ADU is allowed alongside an internal ADU and a JADU. The city will need to update its new ordinance again, and we confirm current rules as it does.
Planning two detached ADUs on a Menlo Park lot
- Sprinklers: an ADU needs fire sprinklers only if the main house requires them.
- Stairs: exterior stairs and landings must stay 4 ft from lot lines, which affects two-story layouts.
- Floor area: one ADU may exceed the lot’s floor area limit by up to 800 sq ft,. With two units, plan which one uses the exemption.
- Connection to the house: internal access between an ADU and the main house needs two fire-rated doors.
- Electrical: two units usually need a load calculation and often a service upgrade.
Building ADUs in Menlo Park with Axiom
See our Menlo Park ADU builder page and Menlo Park service area, read the AB 956 overview, or compare neighboring Atherton and Palo Alto.
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.
Menlo Park Two-ADU FAQ
Can I build two detached ADUs in Menlo Park?
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. Until then, Menlo Park allows one internal ADU, one JADU and one detached ADU.
How large can each ADU be in Menlo Park?
A state-standard detached ADU can have 800 sq ft of livable space. 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 Menlo Park?
16 ft, or 18 ft within a half mile of transit, plus 2 ft for a roof pitch that matches the main house.
How long does ADU review take in Menlo Park?
The city checks completeness within 15 business days and decides within 60 days, or the permit is deemed approved. Review is ministerial, through the building permit.
Is Menlo Park’s ADU ordinance approved by the state?
Yes. On June 15, 2026, HCD found the new ordinance in substantial compliance with state ADU law. It will still need updates for AB 956.
Who builds two-ADU projects in Menlo Park?
Axiom Renovation designs, permits and builds ADUs in Menlo Park 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.