ADU permit cost and fee breakdown in Portola Valley, California
GetYourPermit’s researched permit-fee range for a detached accessory dwelling unit in Portola Valley, with category estimates and direct reference links used in our investigation.
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ADU size
California prohibits development impact fees for ADUs of 750 sq ft or less, so the 749 / 750 / 751 steps are worth comparing.
Estimated total
GetYourPermit researched range at 750 sq ft
$9,235 – $14,450
This estimate combines our fee-schedule research and project-planning experience. Actual charges vary by parcel, plans, valuation, utilities, and outside agencies.
Typical planning amount
$11,730
Modeled at the 600 sq ft reference.
Where the money goes
These are fee components within the permit process, not separate approvals.
- Separate planning / zoning fee$550 – $1,000
Shown only where the City bills Planning or zoning review as a separate fee.
- Building plan check$1,595 – $2,490
The Building Division’s review of the drawings; part of the Building Permit process.
- Building permit issuance$2,900 – $3,560
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
- Separate trade permits$700 – $1,250
Shown separately only where electrical, plumbing, or mechanical permits are billed outside a combination permit.
- School district fees$2,100 – $3,200
Possible school-district developer fees based on current thresholds and scope.
- Utility fees$950 – $2,150
Possible water, sewer, electrical, meter, or capacity-related charges.
- Processing, inspection & records$270 – $550
Fixed processing, inspection, records, and administrative charges.
- Surcharges, taxes & state fees$170 – $250
Percentage surcharges, construction taxes, and State-mandated charges.
The darker segment is the low end of the range; the full bar is the high end.
Published fee references
Building permit issuance
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Residential Building Permit by valuation | Verify on the City’s official website | Formula | Town of Portola Valley FY 2026-27 Fee ScheduleLocation: FY 2026-27 Fee Schedule, p. 11, Building Fees & Permits, Permit FeesConfirms: The current Town schedule publishes the residential valuation brackets, but does not publish a dedicated ADU/JADU Building Permit row. |
| Current dedicated ADU/JADU Town fee | Verify on the City’s official website | Verify on the City’s official website | Quick Overview: ADU/JADU RequirementsLocation: FY 2026-27 Fee Schedule Building Fees & Permits; ADU/JADU requirements page |
Plan check
Review of your drawings for code compliance.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Plan Review fee | Verify on the City’s official website | Formula | Town of Portola Valley FY 2026-27 Fee ScheduleLocation: FY 2026-27 Fee Schedule, p. 11, Building Fees & Permits, Plan Check FeesConfirms: The current schedule lists Town Plan Review at 55% of the permit fee but does not establish that it is the complete ADU/JADU fee path. |
These are estimates, not official fees
Use these figures for early budgeting only. They are not a quote, not a government fee determination, and not legal advice. Actual fees depend on your parcel, your plans, your construction valuation, your utility provider, and the fee schedule in force on the day your permit is issued. Confirm every number with Portola Valley before you commit money.
City reference pages for verification
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