Zoning, building permits and septic rules in Menlo Park, California

Menlo Park’s own rules

• Building code adoptedAdopted

  Construction in Menlo Park city limits, under the 2025 California codes with city amendments.

  • Applications received on or after January 1, 2026 must meet the 2025 California building standards codes, effective January 1, 2026 (Parts 1, 2, 2.5, 3, 4, 5, 6, 7, 8, 10, 11 and 12 of Title 24, with appendices).
  • Applications received before the 2026 effective date remain under the 2022 code series, per the city's December 2025 notice (not opened).
  • Local amendments are in Title 12 (chapters 12.06, 12.08, 12.14, 12.16, 12.18).

  “the following codes have been adopted and amended by the city of menlo park. applications received on or after january 1, 2026, must meet the requirements established in the building codes: 2025 california building standards codes effective january 1, 2026”

• Local zoningPresent (with conditions)

  Land inside Menlo Park city limits, which is governed by the city's own Title 16 (Zoning) of the Menlo Park Municipal Code.

  • Zoning districts, uses and development standards are set by Title 16 and vary by district; see the district-specific claims.
  • Source is the city's eCode360 code, which states it includes legislation through 06-09-2026.

  “title 16 zoning (§ 16.02.010 – § 16.99.070)”

• Zoning districtsPublished

  Single-family zoning districts inside Menlo Park city, as published in Title 16 chapters (the R-1-U (LM) Lorelei Manor district was opened and verified; other district chapters were not opened).

  • Only the R-1-U (LM) chapter 16.17 was opened; the base R-1-U (16.16), R-1-S (16.14) and other district chapters are not verified in this record.

  “development regulations in the r-1-u (lm) district are as follows:”

• Minimum lot sizeDistrict specific (with conditions)

  Lots in the R-1-U (LM) Lorelei Manor single-family district inside Menlo Park city only; not the general single-family districts (R-1-U base chapter 16.16 and R-1-S chapter 16.14 were not opened).

  • Lots in existence before June 1, 2006 use 4,900 sq ft; lots created or subdivided after June 1, 2006 require 7,000 sq ft.
  • Minimum land area per dwelling unit is 4,900 sq ft per the same section (2) of § 16.17.030.
  • Minimum lot dimensions are 40 ft width and 75 ft depth.

  minimum lot area, lots existing before June 1, 2006: >= 4900 sq ft (R-1-U (LM) district only) · minimum lot area, lots created or subdivided after June 1, 2006: >= 7000 sq ft (R-1-U (LM) district only) · minimum lot width: >= 40 ft (R-1-U (LM) district only) · minimum lot depth: >= 75 ft (R-1-U (LM) district only)

  “(1) minimum lot area: four thousand nine hundred (4,900) square feet for lots in existence prior to june 1, 2006 and a minimum of seven thousand (7,000) square feet for any lot created or subdivided after june 1, 2006; (2) minimum land area per dwelling unit: four thousand nine hundred (4,900) square feet; (3) minimum lot dimensions: (i) forty feet (40') width; (ii) seventy-five feet (75') depth;”

• Accessory dwellingsAllowed

  Accessory dwelling units (ADUs) and junior ADUs (JADUs) on residential lots inside Menlo Park city, under the ordinance adopted June 9, 2026 (Ord. 1129).

  • Attached, internal and detached ADUs are permitted in all zoning districts that allow single-, multi-family and mixed-use residential uses, subject to §§ 16.79.050 and 16.79.070.
  • Only one 66314 unit is allowed on a lot (§ 16.79.070(a)).
  • JADUs may be rented but not for less than 30 consecutive days (§ 16.79.060(g)).
  • JADUs cannot be sold separately and need a recorded deed restriction (§ 16.79.060(f)).
  • No ADU or JADU is permitted on a lot where an urban lot split under Chapter 15.31 and a two-unit development under Chapter 16.77 have both been approved (§ 16.79.090(a)).
  • Conditional use permit needed for ADUs that require modification of the chapter's standards (§ 16.79.040).

  minimum JADU floor area: >= 150 sq ft (interior livable space, per § 16.79.060(1)) · maximum JADU floor area: <= 500 sq ft (interior livable space, contained within the single-family residence)

  “(b) jadus subject to the development regulations in section 16.79.060 are a permitted use in all single-family zoning districts.”

• Subdividing landRegulated (with conditions)

  Land divisions inside Menlo Park city limits, under Title 15 (Subdivisions).

  • Title 15 is the city's subdivision code; its chapter-level rules were not opened.

  “title 15 subdivisions (§ 15.04.010 &ndash; § 15.40.060)”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Menlo Park or San Mateo County directly.

• Building permit — Permit requirement for new construction inside Menlo Park city.
• Owner-builder exemption — Owner-builder permit exemption inside Menlo Park city.
• Inspections — Building inspections inside Menlo Park city.
• Certificate of occupancy — Certificate of occupancy for new homes inside Menlo Park city.
• Minimum dwelling size — Minimum dwelling size in Menlo Park single-family districts.

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Off-grid gear

Going off-grid in Menlo Park means bringing your own water and power. The kit we’d start with:

• Water Crystal Quest Filter any source — well, rain, or creek — to drinking-clean.
• Power Bluetti Solar generators and home battery backup for living off the grid.
• Septic Soil percolation test kit Run your own perc test before paying an engineer — the first thing a septic office asks about.
• Water Well water test kit Bacteria, nitrates, hardness — know what the well on a parcel is really pumping.

These are affiliate links — we may earn a commission, at no cost to you. As an Amazon Associate, Bolthole Index earns from qualifying purchases.