ADU permit cost and fee breakdown in Antioch, California
GetYourPermit’s researched permit-fee range for a detached accessory dwelling unit in Antioch, with category estimates and direct reference links used in our investigation.
Prepared by GetYourPermit editorial teamReport an error
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
$12,955 – $22,290
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
$17,170
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$450 – $900
Shown only where the City bills Planning or zoning review as a separate fee.
- Building plan check$3,250 – $4,420
The Building Division’s review of the drawings; part of the Building Permit process.
- Building permit issuance$4,850 – $6,600
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
- Separate trade permits$800 – $1,700
Shown separately only where electrical, plumbing, or mechanical permits are billed outside a combination permit.
- School district fees$1,800 – $3,600
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 – $680
Fixed processing, inspection, records, and administrative charges.
- Surcharges, taxes & state fees$655 – $890
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 fee by total valuation | Set by City formula | Formula | Master Fee Schedule Effective July 1, 2026 as Amended June 9, 2026Location: PDF page 9, Antioch Building Permit Fees table, Effective 7/26/26 columnConfirms: The current official schedule uses a stepped valuation table rather than a flat ADU building-permit amount. |
Plan check
Review of your drawings for code compliance.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Plan-check fee | 67% formula | Formula | Master Fee Schedule Effective July 1, 2026 as Amended June 9, 2026Location: PDF page 8, Building Fees (Cont.), Plan Check Fee rowConfirms: The City schedule sets plan check at 67% of the building-permit fee. |
Impact fees
Development impact fees. Prohibited for ADUs of 750 sq ft or less.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| City development impact fees for an ADU smaller than 750 square feet | $0 | Flat fee | Antioch Municipal Code § 9-3.60 — Calculation and Payment of Development Impact FeesLocation: Municipal Code § 9-3.60(D)(3)Confirms: The City code states that DIFs are not collected on ADUs smaller than 750 square feet. |
| City development impact fees for an ADU of at least 750 square feet on a single-family property | Set by City formula | Formula | Antioch Municipal Code § 9-3.60 — Calculation and Payment of Development Impact FeesLocation: PDF page 7, Development Impact Fees table; Municipal Code § 9-3.60(A) and (D)(2)Confirms: The current City rates and municipal code together establish a proportional formula capped at the multifamily rate. |
Inspection
Field inspections during construction.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Energy inspection fee | 2% formula | Formula | Master Fee Schedule Effective July 1, 2026 as Amended June 9, 2026Location: PDF page 8, Building Fees (Cont.), Energy Inspection Fee rowConfirms: The City schedule sets the energy inspection fee at 2% of the building-permit fee. |
Technology & surcharges
Records, technology, and general plan surcharges.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Technology fee | 7.5% formula | Formula | Master Fee Schedule Effective July 1, 2026 as Amended June 9, 2026Location: PDF page 8, Building Fees (Cont.), Technology Fee rowConfirms: The City schedule sets the technology fee at 7.5% of the building-permit fee. |
Surcharges, taxes & state fees
Percentage surcharges, construction taxes, and State-mandated charges.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| General Plan maintenance fee | 6% formula | Formula | Master Fee Schedule Effective July 1, 2026 as Amended June 9, 2026Location: PDF page 6, Planning Fees, General Plan Maintenance rowConfirms: The current schedule expresses the General Plan maintenance charge as a percentage 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 Antioch before you commit money.
City reference pages for verification
Back to Antioch · Permit process · Build a permit report · How we build these estimates