ADU permit cost and fee breakdown in Walnut Creek, California
GetYourPermit’s researched permit-fee range for a detached accessory dwelling unit in Walnut Creek, 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
$7,400 – $17,850
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
$11,600
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 – $1,300
Shown only where the City bills Planning or zoning review as a separate fee.
- Building plan check$1,600 – $3,500
The Building Division’s review of the drawings; part of the Building Permit process.
- Building permit issuance$1,600 – $3,500
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
- Separate trade permits$700 – $1,600
Shown separately only where electrical, plumbing, or mechanical permits are billed outside a combination permit.
- School district fees$1,500 – $3,000
Possible school-district developer fees based on current thresholds and scope.
- Utility fees$800 – $3,500
Possible water, sewer, electrical, meter, or capacity-related charges.
- Processing, inspection & records$350 – $800
Fixed processing, inspection, records, and administrative charges.
- Surcharges, taxes & state fees$250 – $650
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
Plan check
Review of your drawings for code compliance.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Building plan review | 100% formula | Formula | Master Fee Schedule — Fiscal Years 2026 and 2027Location: Master Fee Schedule FY 2026/27, Plan Review Fees, A. Building Plan Review FeesConfirms: The City states building plan review is 100% of the building permit fee. |
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 Walnut Creek before you commit money.
City reference pages for verification
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