Two Detached ADUs in Redwood City (AB 956, 2027)
Plan Two ADUs in Redwood City: Free Site Assessment
Redwood City ADU rules today (2026)
From January 1, 2027, state law (AB 956) requires cities, including Redwood City, to approve up to two detached ADUs on a lot with a single-family home. Redwood City has worked with HEART of San Mateo County on pre-reviewed ADU designs. Here is how the new law and the city’s current rules fit together.
- Code: ADU rules are in Zoning Code Article 37, covering development standards, statewide exemption ADUs, rental and sale limits, and application review. It was amended in 2021 and again in August 2024 (Ordinance 1130-890).
- Units allowed now: the city’s ADU code allows one ADU and one JADU on a single-family lot. State law also allows a conversion ADU plus a detached ADU plus a JADU.
- Statewide exemption ADUs: the code has a section for state-exempt ADUs, which state law sets at up to 800 sq ft, 16 ft tall, with 4 ft side and rear setbacks.
- Process: ADUs are reviewed ministerially, and state law requires a decision within 60 days.
- Pre-reviewed designs: the city partnered with HEART of San Mateo County on studio, one- and two-bedroom designs, reported as expected in early 2025.
We did not find an official city ADU page with current size, height or parking figures, so we confirm those with the city on each project.
What changes on January 1, 2027
AB 956 raises the number of detached ADUs the city must approve on a single-family lot to two, both new construction. The city may limit each of the two to 800 sq ft of living space and apply its height limits, and side and rear setbacks can be no more than 4 ft. Where two detached ADUs are built, the city does not have to approve a JADU on the same lot. The law also limits how homeowners associations can restrict these units.
Redwood City’s code allows one ADU per lot, so it will need to update Article 37 to allow two detached units. Pre-reviewed studio and one-bedroom designs may fit within the 800 sq ft cap. We will confirm how the city writes these changes as it updates its code.
Recent Axiom work
Professional photos from a recent Axiom Renovation full remodel and addition in Los Gatos.
Planning two detached ADUs on a Redwood City lot
- Historic properties: an ADU on a property listed on the California Register must follow the Secretary of the Interior’s Standards.
- Rentals and sale: Article 37 bars short-term rentals and separate sale of ADUs.
- Site layout: we map setbacks, trees, slopes and utility routes before placing two units.
- Electrical: two ADUs usually need a load calculation and often a service upgrade.
Building ADUs in Redwood City with Axiom
Visit our Redwood City ADU builder page and Redwood City service area, or read the AB 956 overview. Nearby, see the guides for San Carlos and Atherton.
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.
Redwood City Two-ADU FAQ
Can I build two detached ADUs in Redwood City?
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, the city’s code allows one ADU and one JADU.
How large can each ADU be in Redwood City?
Under AB 956, the city may limit each of two detached ADUs to 800 sq ft of living space. We confirm the city’s current size limits on each project.
How tall can a detached ADU be in Redwood City?
AB 956 lets the city apply its height limits. A state-exempt ADU can always be at least 16 ft tall. We confirm the current local limit with the city.
How long does ADU approval take in Redwood City?
ADUs are reviewed ministerially, and state law requires the city to approve or deny a complete application within 60 days.
Can I rent out an ADU in Redwood City?
Yes, but Article 37 bars short-term rentals, and an ADU cannot be sold separately from the main house.
Who builds two-ADU projects in Redwood City?
Axiom Renovation designs, permits and builds ADUs in Redwood City 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.