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LotlineADU permit guides

City notesSan Mateo County, California

Getting an ADU permit in Menlo Park

Menlo Park's current ADU checklist is dated March 2026 and is built around the state's two-step review. The paperwork is heavier on engineering and trees than most, and the way the city counts its 60 days is worth reading closely.

At a glance

15 business days
completeness review, on days City Hall is open2
60 calendar days
to decide, counted from the completeness date2
500 sq ft
above this, grading and drainage plans are needed2

Key points

  • The city's checklist is itself a required submittal, initialled item by item.12
  • ADUs over 500 sq ft need grading, drainage and improvement plans.2
  • The city counts its 60 days from the date it determines completeness.2
  • Heritage and street trees, including a neighbor's, can trigger an arborist report.2

State rule and Menlo Park practice, side by side

Where the two say the same thing, and where they differ.

Completeness review

California statute

The permitting agency has 15 business days from receiving an ADU application to decide whether it is complete and tell the applicant in writing.3

Menlo Park

The city counts the 15 business days as days its City Hall Administration building is open to the public.2

After a resubmittal

California statute

A resubmittal gets the same 15-business-day completeness review as the first application.3

Menlo Park

Each resubmittal starts a new 15-business-day completeness review.2

When the 60 days start

California statute

Where the lot already has a single-family or multifamily dwelling, the agency must approve or deny within 60 days from the date it receives a completed application.3

Menlo Park

The city starts its 60 calendar days on the date completeness is determined, and counts days City Hall is closed.2

The statute counts from receipt of a completed application; the city's handout counts from its own determination. If the city takes the full 15 business days to confirm completeness, the two readings can differ by about three weeks.

After a denial

California statute

A denial must come with a full set of written comments listing what is defective or deficient and how to remedy it, within the same 60-day period.3

Menlo Park

After a denial, the applicant can resubmit and a new 60-calendar-day review begins.2

How the city runs the review

Menlo Park describes a two-step process for ministerial ADU applications: a completeness review followed by an approval or denial period.2 The rules for the units themselves are in Chapter 16.79 of the city's Zoning Ordinance, read together with the standards of your zoning district.2

One sequencing point catches people out. If your project needs discretionary review, such as a use permit, that review has to be finished before the ministerial process begins.2 The 15 and 60 day periods don't start to help you until then.

Staff also recommend a visit to the public information counter to talk with Planning, Building and Engineering before you apply.1 Given how many of the items below belong to Engineering, that conversation is worth having early.

The checklist is part of the application

The city's ADU page states that its checklist is required for new ADU applications.1 You submit the checklist itself, initialling each item to show it has been included and writing "N/A" where an item doesn't apply.2

Items that go beyond a typical plan set

Survey and diagrams. The plan set list includes a boundary and topographic survey.2 On single-family lots it also includes floor area and building coverage diagrams.2 A survey takes time to commission, so order it before the drawings are finished.

Proof that an existing structure is legal. If you are converting an accessory building that wouldn't otherwise meet the ADU location or height rules, you have to document that it was legally permitted.2 A property assessment record from the San Mateo County Assessor's Office is one accepted form.2

Engineering documents. This is where Menlo Park asks for the most:

  • Grading, drainage and improvement plans for ADUs greater than 500 square feet2
  • A grading plan showing cut and fill for hillside projects and in Sharon Heights2
  • An impervious area worksheet and a C.3 and C.6 development review checklist2
  • Extra floodplain or creekside documentation for sites in flood zones or near creeks2

Easements. The checklist is blunt on this: a project that conflicts with a recorded easement can't be approved unless the easement is formally vacated, modified or released.2 Pull your title report and plot every easement on the site plan before fixing the ADU's position.

Trees. An arborist report is required when the project is close to heritage trees or street trees, and that includes trees on adjacent properties that construction could affect.2 Pruning more than 25% of a heritage tree's crown needs a separate permit application for each tree.2

Junior ADUs. The deed restriction item on the checklist applies only to junior ADUs.2

Our read

Menlo Park's process is clear and well documented, which is a point in its favor. The delays we would expect come from three places: the survey, the engineering package on anything over 500 square feet, and trees near the build area. All three are things you can start on before submitting. On timing, keep your own dated record of when you submitted and when the city confirmed completeness, since the city and the statute describe the start of the 60 days differently.

Common questions

When does Menlo Park's 60-day review start?

The city's checklist starts it on the date completeness is determined.2 The statute counts from the date the agency receives a completed application.3 How the clocks work statewide is in our timeline guide.

Do I need a survey for an ADU in Menlo Park?

A boundary and topographic survey is on the city's list of sheets for a complete plan set.2

When does Menlo Park require a grading and drainage plan?

For ADUs greater than 500 square feet.2 If the city lists it as missing, see how to answer an incomplete notice.

Keep reading

About this page

Written by
The Lotline Editorial Team. Editorial policy
Where it comes from
We wrote this from material published by City of Menlo Park and California Legislative Information. You'll find each document, and the part we used, under References below.
How it was checked
Before publishing, we checked each statement against the original wording of its source. How we work
Last reviewed
. Rules and city procedures change, so confirm current requirements with your permitting agency.
Corrections
Email support@lotlinepermits.com. We check every report against the document and fix what is wrong.

References

  1. 1What is the permit process? (Accessory dwelling units)City of Menlo Park. Read on November 10, 2026.Cited: web page.
  2. 2Accessory Dwelling Unit (ADU) Application ChecklistCity of Menlo Park, Community Development, Planning Division. Dated March 19, 2026. Read on November 10, 2026.Cited: page 1; page 3, Required Engineering Documents; page 1, General Information; page 4, Arborist Report; page 1, Project Plans; page 2; page 2, Property Assessment Record; page 3, Easement Agreements; page 4, Heritage Tree Removal Permit Applications; page 2, Deed Restriction.
  3. 3California Government Code, Title 7, Division 1, Chapter 13, Article 2 (Sections 66314 to 66331)California Legislative Information. Read on November 10, 2026.Cited: § 66317(a)(2)(A); § 66317(a)(2)(E); § 66317(a)(3); § 66317(b).

General information, not legal advice. Read the disclaimer.