Permit guides

ADU Permits in Menlo Park: a Homeowner's Guide

Menlo Park's lots hide the details that make or break an ADU: heritage trees, clay soil, and side yards barely wide enough to carry lumber through.

Last updated October 2026. Rules change; always confirm current requirements with the city before you build.

Who handles your permit

ADU permits in Menlo Park run through the Community Development Department (Building, Planning, and Housing divisions). One thing to know upfront: fire protection comes from the Menlo Park Fire Protection District — a separate special district, not a city department — so fire approval is its own coordination track.

What you can build

1,200 sq ftMax for a detached ADU under state law

Heritage treesProtected by their own city permit process — check before designing near one

Flood zonesProperties east of Highway 101 and near the bay need flood-zone verification

Clay soilParts of the city sit on clay that moves seasonally — foundations must account for it

4 ftMinimum side and rear setbacks for detached ADUs

60 daysState deadline for the city to act on a complete application

The pre-design checklist

Before paying for drawings on a Menlo Park lot, gather answers to these — any one of them can change the design:

Zoning district, allowed floor area, and building height for the parcel, from the city's zoning map
Heritage trees on or near the building footprint — the city protects them through a separate permit process
Flood zone status, especially east of Highway 101 and near the bay
Electrical panel capacity, and whether the service supports an all-electric unit or a heat pump
Age and condition of the sewer lateral, which the ADU will share with the main house
Site drainage and soil type — clay soils mean movement-tolerant foundations

What goes into the submittal

Menlo Park expects a complete plan set: area plan, site plan, streetscape, existing and proposed floor plans and elevations, sections, square-footage and coverage calculations, landscape and open-space diagrams, roof plan, grading and drainage, utilities, and erosion control. Projects near older structures may need a historic significance evaluation, and a color and materials board goes in as its own plan sheet.

Access is the hidden constraint. Many lots in neighborhoods like Allied Arts and the Willows have narrow side yards — materials arrive by hand and excavation uses small equipment. It doesn't stop the project, but it lengthens the schedule. Separately, plan coordination time for a new address, a separate meter if you want one, sprinklers in some cases, and the sewer lateral connection.

Where applications usually get stuck

Heritage trees. Their permit process runs parallel to the ADU permit — discover a protected tree late and the design may need rework.
The fire district. A separate agency with its own review means separate comments and its own timeline.
Utility coordination. Sewer lateral condition, panel capacity, and meter separation are the quiet schedule-killers.

Not sure where to start? That's the part we do. We check your property against the requirements, coordinate the plans and specialists, and manage the submittal and corrections — one point of contact.

Tell us what you need help with.

Not sure where to start? That's what we're here for.

Send your project

Erik — (916) 540-8960 · Vall — (916) 956-8106
office@pcg-engineering.pro