ADU permit cost and fee breakdown in Folsom, California
GetYourPermit’s researched permit-fee range for a detached accessory dwelling unit in Folsom, 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
$4,897 – $9,652
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
$8,042
Modeled at the 600 sq ft reference.
Where the money goes
These are fee components within the permit process, not separate approvals.
- Building permit issuance$4,852
The permit issuance charge; where plan check is bundled, the combined amount is carried here.
- School district fees$45 – $3,300
Possible school-district developer fees based on current thresholds and scope.
- Utility fees$0 – $1,300
Possible water, sewer, electrical, meter, or capacity-related charges.
- Surcharges, taxes & state fees$0 – $200
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 |
|---|---|---|---|
| Detached and Attached ADU permit | $4,852 | Flat fee | July 1, 2026 CDD User FeesLocation: CDD User Fees effective July 1, 2026, Building Fees A rows 18 and notes [a]–[b]Confirms: The current City schedule explicitly lists the dedicated ADU fee and states what it includes. |
| Junior ADU permit | $2,329 | Flat fee | July 1, 2026 CDD User FeesLocation: CDD User Fees effective July 1, 2026, Building Fees A row 19 and note [b]Confirms: The current City schedule explicitly lists the dedicated JADU fee and states what it includes. |
Impact fees
Development impact fees. Prohibited for ADUs of 750 sq ft or less.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| ADU impact-fee rule | From $0 | Formula | North of 50 Development Impact Fees and Permit FeesLocation: North of 50 schedule page 4 and Folsom Plan Area schedule page 2, ADU threshold and ratio rowsConfirms: Both current City impact-fee schedules explicitly provide the ADU under-750-square-foot $0 rule and greater-than-750-square-foot proportional calculation. |
School district fees
Developer fees charged by the local school district.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| ADU school-fee lookup | Verify on the City’s official website | Verify on the City’s official website | North of 50 Development Impact Fees and Permit FeesLocation: Current impact schedules, Citywide Impact Fees — School Impact Mitigation Admin FeeConfirms: The City schedules identify the City administrative layer but not the applicable school-district development-fee amount, so no district numerical rate is recorded. |
Utility connection
Water, sewer, and electrical connection or capacity charges.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| ADU utility connection and capacity lookup | Verify on the City’s official website | Verify on the City’s official website | North of 50 Development Impact Fees and Permit FeesLocation: Current impact schedules, sewer and water fee sectionsConfirms: The City schedules expose current base water/sewer tables but require parcel and project classification before an ADU utility charge can be selected. |
Surcharges, taxes & state fees
Percentage surcharges, construction taxes, and State-mandated charges.
| Fee | Amount | Basis | Source |
|---|---|---|---|
| Building Permit processing and surcharge lookup | From $81 | Formula | July 1, 2026 CDD User FeesLocation: CDD User Fees effective July 1, 2026, Building Fees D–E and A note [b]Confirms: The current City schedule states the processing, plan-review, and General Plan formulas and separately says the dedicated ADU/JADU figures include processing, plan review, and permit. |
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 Folsom before you commit money.
City reference pages for verification
Back to Folsom · Permit process · Build a permit report · How we build these estimates