ADU permit cost and fee breakdown in Redwood City, California
GetYourPermit’s researched permit-fee range for a detached accessory dwelling unit in Redwood City, 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
$2,700 – $14,200
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
$10,500
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$0 – $250
Shown only where the City bills Planning or zoning review as a separate fee.
- Building plan check$1,165 – $2,330
The Building Division’s review of the drawings; part of the Building Permit process.
- Building permit issuance$1,165 – $2,331
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
- Separate trade permits$200 – $600
Shown separately only where electrical, plumbing, or mechanical permits are billed outside a combination permit.
- School district fees$0 – $3,100
Possible school-district developer fees based on current thresholds and scope.
- Utility fees$0 – $5,000
Possible water, sewer, electrical, meter, or capacity-related charges.
- Processing, inspection & records$110 – $439
Fixed processing, inspection, records, and administrative charges.
- Surcharges, taxes & state fees$60 – $150
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 |
|---|---|---|---|
| New ADU, 0–400 square feet or qualifying garage conversion | $4,000 | Flat fee | Master Fee Schedule — Effective 7/1/2026Location: Master Fee Schedule, page 7, New ADUConfirms: The current schedule lists $3,999.53. |
| New ADU, 401–600 square feet | $4,661 | Flat fee | Master Fee Schedule — Effective 7/1/2026Location: Master Fee Schedule, page 7, New ADUConfirms: The current schedule lists $4,660.62. |
| New ADU, 601–800 square feet | $5,322 | Flat fee | Master Fee Schedule — Effective 7/1/2026Location: Master Fee Schedule, page 7, New ADUConfirms: The current schedule lists $5,321.71. |
Plan check
Review of your drawings for code compliance.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Building permit plan-check payment | 50% formula | Formula | Master Fee Schedule — Effective 7/1/2026Location: Master Fee Schedule, Building Permit Fees, Plan CheckConfirms: The City identifies the plan-check payment as a component of building permit fees. |
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 Redwood City before you commit money.
City reference pages for verification
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