ADU permit cost and fee breakdown in Millbrae, California
GetYourPermit’s researched permit-fee range for a detached accessory dwelling unit in Millbrae, 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
$5,950 – $16,250
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
$10,200
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$500 – $1,250
Shown only where the City bills Planning or zoning review as a separate fee.
- Building plan check$1,700 – $4,400
The Building Division’s review of the drawings; part of the Building Permit process.
- Building permit issuance$2,100 – $5,200
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
- Separate trade permits$600 – $1,500
Shown separately only where electrical, plumbing, or mechanical permits are billed outside a combination permit.
- School district fees$350 – $1,100
Possible school-district developer fees based on current thresholds and scope.
- Utility fees$350 – $1,850
Possible water, sewer, electrical, meter, or capacity-related charges.
- Processing, inspection & records$220 – $650
Fixed processing, inspection, records, and administrative charges.
- Surcharges, taxes & state fees$130 – $300
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-review fees | Verify on the City’s official website | Verify on the City’s official website | Building DivisionLocation: City Fee Schedule J-1; Building Division landing pageConfirms: Official City source for verifying Current ADU building and plan-review fees. |
Impact fees
Development impact fees. Prohibited for ADUs of 750 sq ft or less.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Current ADU development impact fee | Verify on the City’s official website | Verify on the City’s official website | Accessory Dwelling UnitsLocation: Accessory Dwelling Units page, development impact-fee discussion |
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 Millbrae before you commit money.
City reference pages for verification
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