Two Detached ADUs in Dublin (AB 956, 2027)
Plan Two ADUs in Dublin: Free Site Assessment
Dublin ADU rules today (2026)
From January 1, 2027, state law (AB 956) requires cities, including Dublin, to approve up to two detached ADUs on a lot with a single-family home. Dublin rewrote its ADU rules in November 2025 and offers eight permit-ready prototype plans. Here is how those rules meet the new law.
- Units allowed now: one ADU plus one JADU on a single-family lot. A JADU can pair with a detached ADU (DMC Ch. 8.80, replaced by Ordinance 9-25, adopted November 4, 2025).
- Sizes: the city’s ADU code allows a detached ADU up to 1,200 sq ft. An attached ADU on an existing house is limited to the least of 50% of the house, 850 sq ft (studio or one bedroom) or 1,000 sq ft (two or more). JADUs up to 500 sq ft. Minimum size is 150 sq ft.
- Height: 16 ft for a detached ADU; 18 ft within a half-mile walk of transit, plus 2 ft for roof pitch. An outside stair to a second-story ADU may not be visible from the front.
- Setbacks: no more than 4 ft side and rear. Not in the established front setback, except as needed for an 800 sq ft ADU.
- Parking: one space, none for a studio. Exemptions include transit, conversions and filing with a new house. Spaces can be tandem, uncovered or in setbacks. No garage replacement.
- Process: ministerial, with a decision in 60 days or the permit is deemed approved.
- Prototype plans: eight permit-ready plans (five attached or detached, three garage conversions), studio to two bedrooms, 224 to 909 sq ft.
What changes on January 1, 2027
AB 956 raises the number of detached ADUs Dublin must approve on a single-family lot from one to two, both new construction. Each 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. The law also includes protections for owners in homeowners associations.
Dublin allows one new ADU today, so a second detached unit is new. Dublin’s 1,200 sq ft detached limit is above the 800 sq ft each unit may be held to in a two-unit project. Several of the city’s prototype plans fall in the 224 to 909 sq ft range, so some may fit an 800 sq ft cap. Dublin will need to update its ordinance, and we will confirm the 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 Dublin lot
- Lot coverage: the house and ADUs together are capped at 60% lot coverage. This is often the limit that decides whether two units fit.
- Design: ADUs must match the house. No balconies facing a side lot line, balconies at least 10 ft from side and rear lines, and no rooftop decks.
- Parking: two non-studio units may each need a space unless an exemption applies. Tandem and uncovered spaces are allowed.
- Utilities: public water and sewer are required. Two ADUs usually need a load calculation and often an electrical service upgrade.
- ADU Accelerator: Dublin is part of the Tri-Valley/East Bay ADU Accelerator. Units over 1,000 sq ft are not eligible.
- Use and sale: owner occupancy applies only to a JADU. Rentals must be longer than 30 days, and separate sale is allowed only under Gov. Code §66341.
Building ADUs in Dublin with Axiom
See our Dublin ADU builder page and our Dublin service area, read the AB 956 overview, or compare neighboring Pleasanton and San Ramon.
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.
Dublin Two-ADU FAQ
Can I build two detached ADUs in Dublin?
From January 1, 2027, AB 956 requires Dublin to approve up to two detached, new-construction ADUs on a single-family lot that meets objective standards. Today Dublin allows one ADU plus one JADU.
How large can each ADU be in Dublin?
The city’s ADU code allows a detached ADU up to 1,200 sq ft today. 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 Dublin?
16 ft, or 18 ft within a half-mile walk of transit, plus 2 ft for a roof pitch.
Does Dublin have permit-ready ADU plans?
Yes. Dublin offers eight prototype plans, five attached or detached and three garage conversions, from 224 to 909 sq ft and from studio to two bedrooms.
Will lot coverage limit two ADUs in Dublin?
It can. Dublin caps the house and ADUs together at 60% lot coverage, so we check coverage first when planning two detached units.
Who builds two-ADU projects in Dublin?
Axiom Renovation designs, permits and builds ADUs in Dublin 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; Dublin ADU page; Dublin prototype ADU checklist. This page is general information, not legal advice. Local rules change; we confirm current requirements with the city for every project.