ADU permit cost and fee breakdown in Sunnyvale, California
GetYourPermit’s researched permit-fee range for a detached accessory dwelling unit in Sunnyvale, 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
$7,240 – $12,420
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
$9,785
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$350 – $700
Shown only where the City bills Planning or zoning review as a separate fee.
- Building plan check$2,600 – $4,000
The Building Division’s review of the drawings; part of the Building Permit process.
- Building permit issuance$3,715 – $5,710
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
- Separate trade permits$240 – $520
Shown separately only where electrical, plumbing, or mechanical permits are billed outside a combination permit.
- School district fees$0 – $650
Possible school-district developer fees based on current thresholds and scope.
- Utility fees$150 – $500
Possible water, sewer, electrical, meter, or capacity-related charges.
- Processing, inspection & records$125 – $220
Fixed processing, inspection, records, and administrative charges.
- Surcharges, taxes & state fees$60 – $120
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 |
|---|---|---|---|
| Building permit valuation lookup | Set by City formula | Formula | FY 2026/27 Building Permit FeesLocation: FY 2026/27 Building Permit Fees, PDF page 2, Building Permit Fee TableConfirms: The City publishes a valuation-tier formula rather than an ADU flat rate. |
| Permit issuance | $43 | Flat fee | FY 2026/27 Building Permit FeesLocation: FY 2026/27 Building Permit Fees, PDF page 1, Permit IssuanceConfirms: The City lists $42.50 for each issued building project. |
Plan check
Review of your drawings for code compliance.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Plan check | 70% formula | Formula | FY 2026/27 Building Permit FeesLocation: FY 2026/27 Building Permit Fees, PDF page 1, Plan CheckConfirms: The City schedule sets plan check at 70% 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 Sunnyvale before you commit money.
City reference pages for verification
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