ADU permit cost and fee breakdown in Los Altos Hills, California
GetYourPermit’s researched permit-fee range for a detached accessory dwelling unit in Los Altos Hills, 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
$7,100 – $18,800
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
$11,950
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$600 – $1,500
Shown only where the City bills Planning or zoning review as a separate fee.
- Building plan check$1,800 – $4,600
The Building Division’s review of the drawings; part of the Building Permit process.
- Building permit issuance$2,100 – $5,400
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
- Separate trade permits$600 – $1,750
Shown separately only where electrical, plumbing, or mechanical permits are billed outside a combination permit.
- School district fees$1,500 – $3,300
Possible school-district developer fees based on current thresholds and scope.
- Utility fees$200 – $1,200
Possible water, sewer, electrical, meter, or capacity-related charges.
- Processing, inspection & records$200 – $700
Fixed processing, inspection, records, and administrative charges.
- Surcharges, taxes & state fees$100 – $350
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 |
|---|---|---|---|
| Current ADU building and plan-check fee lookup | Verify on the City’s official website | Verify on the City’s official website | Building Fee Schedule and PaymentLocation: Building Fee Schedule and Payment, valuation section; May 14, 2026 fee-study effective-date slides; ADU Building Permit Issuance sectionConfirms: Official materials prove an ADU fee path and valuation authority but do not provide a verified current fee schedule. |
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 Los Altos Hills before you commit money.
City reference pages for verification
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