ADU permit cost and fee breakdown in Oxnard, California
GetYourPermit’s researched permit-fee range for a detached accessory dwelling unit in Oxnard, 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
$5,777 – $15,750
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
$10,006
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$300 – $700
Shown only where the City bills Planning or zoning review as a separate fee.
- Building plan check$900 – $1,600
The Building Division’s review of the drawings; part of the Building Permit process.
- Building permit issuance$1,050 – $1,850
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
- Separate trade permits$350 – $620
Shown separately only where electrical, plumbing, or mechanical permits are billed outside a combination permit.
- School district fees$1,500 – $3,500
Possible school-district developer fees based on current thresholds and scope.
- Utility fees$1,500 – $7,000
Possible water, sewer, electrical, meter, or capacity-related charges.
- Processing, inspection & records$37 – $150
Fixed processing, inspection, records, and administrative charges.
- Surcharges, taxes & state fees$140 – $330
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 | From $32 | Formula | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF pages 10 and 14–15, Section IX.A.1 and Section IX.C, Table 1Confirms: The current City schedule uses a stepped construction-valuation formula for the core building permit fee. |
| New-construction electrical permit fee | 13% formula | Formula | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF page 14, Section IX.A.17.aConfirms: The City schedule calculates new-construction electrical permits as 13% of the building permit fee. |
| New-construction mechanical permit fee | 7% formula | Formula | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF page 14, Section IX.A.17.bConfirms: The City schedule calculates new-construction mechanical permits as 7% of the building permit fee. |
| New-construction plumbing permit fee | 13% formula | Formula | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF page 14, Section IX.A.17.cConfirms: The City schedule calculates new-construction plumbing permits as 13% of the building permit fee. |
Plan check
Review of your drawings for code compliance.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Building plan-review fee | 85% formula | Formula | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF page 10, Section IX.A.2.a, Building Plan Review FeeConfirms: The current City schedule sets building plan review at 85% of the Table 1 building permit fee. |
Impact fees
Development impact fees. Prohibited for ADUs of 750 sq ft or less.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| City impact fees for an ADU under 750 sq. ft. | $0 | Flat fee | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF page 32, Section X, Accessory Dwelling UnitsConfirms: The current schedule says City impact fees cannot be charged for an ADU smaller than 750 square feet. |
| Proportional City impact fees for an ADU of 750 sq. ft. or more | Set by City formula | Formula | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF page 32, Section X, Accessory Dwelling UnitsConfirms: The City schedule states that applicable residential impact fees are proportional to the ADU-to-primary-dwelling floor-area ratio. |
Inspection
Field inspections during construction.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Residential energy-conservation review and inspection fee | $0.06 / sq ft | Per square foot | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF pages 12–13, Section IX.A.11, Energy Conservation FeeConfirms: The City schedule sets this residential component at $0.062 per conditioned square foot. |
Surcharges, taxes & state fees
Percentage surcharges, construction taxes, and State-mandated charges.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Permit issuance fee | $45 | Flat fee | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF page 13, Section IX.A.15Confirms: The City publishes a separate $45 permit or revision issuance charge. |
| Supplemental permit issuance fee | $15 | Flat fee | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF page 13, Section IX.A.15Confirms: The City publishes a separate $15 issuance charge for a qualifying supplemental permit for the same project on the same visit. |
| Permit Center Improvement surcharge | 5% formula | Formula | Fees Charged Developers — Fees Revised July 18, 2026Location: PDF page 22, Section XIConfirms: The current schedule applies a 5% surcharge to processing 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 Oxnard before you commit money.
City reference pages for verification
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