ADU Builder in Menlo Park, CA
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Menlo Park's New ADU Rules
Menlo Park adopted a new ADU ordinance (Ordinance 1129) effective July 10, 2026. Under Chapter 16.79:
- JADU: up to 500 sq ft, plus up to 150 sq ft for an entry.
- Detached ADU: 800 sq ft guaranteed, 16 feet tall (18 near transit, plus 2 feet to match the roof pitch).
- Attached ADU: 850 sq ft for one bedroom or less, 1,000 sq ft for more, capped at 50% of the main home; up to 25 feet or the zoning limit.
- Accessible units may add 100 sq ft.
- Setbacks: 4 feet side and rear; none for conversions within an existing footprint.
- Parking: none for most ADUs and JADUs, and converted garage spaces need not be replaced.
- Rentals: 30-day minimum; owner occupancy only for a JADU sharing a bathroom with the main house.
ADU Construction
How Approval Works
The City checks completeness within 15 business days and approves or denies within 60 calendar days. Menlo Park also has a pre-reviewed ADU plan program, though each site still needs its own building permit.
Outside approvals: Menlo Park Fire Protection District, (650) 688-8400, and West Bay Sanitary District, (650) 321-0384, at 500 Laurel Street, may each require their own permit, plan review and inspection. Their approvals are uploaded to ACA, and the City will not issue the building permit until both sign off. West Bay Sanitary uses its own eTRAKit portal.
701 Laurel Street, Menlo Park, CA 94025 · City Hall (650) 330-6600
Building permits (650) 330-6704, Pe********@*******rk.gov · Inspections (650) 330-6767 · Planning (650) 330-6702
Building counter Monday to Thursday, 7:30 a.m. to 5:30 p.m., and alternate Fridays 8 a.m. to 5 p.m. (closed the other Fridays). Planning counter 1 to 5 p.m. on open days. Permitting is fully digital in Accela Citizen Access (ACA), and inspections are scheduled online or by phone.
Design Considerations
Heritage trees: native oaks 10 inches or more in diameter and other trees 15 inches or more, measured at 54 inches, plus trees designated by the City Council. An arborist report is required when work is near a heritage tree.
Energy: Menlo Park’s local energy code adds electrification and EV charging requirements based on work scope. Pre-wiring for future electric appliances is required when work touches a space with a gas appliance or upgrades the main panel, and larger alterations to homes built before 2011 must include two of nine listed efficiency measures, such as a heat-pump water heater, unless the home already has a Home Energy Score of 7 or higher.
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Other Menlo Park services: Bathrooms · Kitchens · Additions · New Homes · Menlo Park overview
Same service nearby: Atherton · Palo Alto · Los Altos
See how to build an ADU.
Menlo Park ADU Builder FAQ
How big can an ADU be in Menlo Park?
Detached ADUs are guaranteed 800 sq ft; attached ADUs up to 850 or 1,000 sq ft depending on bedrooms, capped at 50% of the home.
How long does ADU approval take?
15 business days for completeness, then up to 60 calendar days to decide.
Is parking required?
Not for most ADUs and JADUs.
Does Menlo Park have pre-approved ADU plans?
It has a pre-reviewed ADU plan program; each site still needs a building permit.