Santa Rosa, CA Accessory Structures: ADU Impact Fees (2026)
Key Facts
- Fee waiver threshold
- 750 sq ft or smaller, or conversion
- Above-threshold fee rule
- Charged proportionate to sq footage
- JADU utility fees
- Waived entirely, any size
- Governing cite
- § 20-42.130(D)(3)(a)-(b)
Summary
Santa Rosa exempts small accessory dwelling units from utility connection fees entirely: units 750 square feet or smaller, and any internal conversion, pay no new connection fee or capacity charge. Any larger ADU still pays impact fees, but only in proportion to its square footage against the primary dwelling's.
3. Utility connections and fees. a. Except as provided in Subsection D.3.b, a separate new utility connection and payment of a connection fee or capacity charge pursuant to State law and City fee schedule will be required for any new accessory dwelling unit. b. No new or separate utility connection or related connection fee or capacity charge will be required for accessory dwelling units that are internal conversions of existing space within a single-family residence or an accessory structure, or for accessory dwelling units that are 750 square feet or smaller. Any impact fee charged for an accessory dwelling unit of 750 square feet or more shall be charged proportionately in relation to square footage of the primary dwelling unit.
Full Breakdown
130(D)(3) of the Santa Rosa City Code splits ADU utility and impact fees into two tracks. ' For anything larger than that 750-square-foot threshold, the same subsection requires that 'any impact fee charged for an accessory dwelling unit of 750 square feet or more shall be charged proportionately in relation to square footage of the primary dwelling unit,' so a 1,000-square-foot ADU on a lot with a 2,000-square-foot primary house pays half the fee a comparable new single-family home would owe, rather than the full flat rate.
c states 'No new or separate utility connection and no connection fee for water, sewer, or power is required for a junior accessory dwelling unit' at all, regardless of size.
Violations & Fines
An applicant charged a flat, non-proportional impact fee on an ADU larger than 750 square feet has grounds to challenge the charge before the Department under Section 20-42.130(D)(3)(b), since the ordinance requires the fee be scaled to the ADU's share of the primary dwelling's square footage, not billed at the same rate as new construction of a full home.
Frequently Asked Questions
Do I pay a sewer or water connection fee for a small Santa Rosa ADU?
How is the impact fee calculated for a larger Santa Rosa ADU?
Do junior accessory dwelling units pay any connection fees in Santa Rosa?
Sources & Official References
Other rules in Santa Rosa
California rules heatmap·Compare Santa Rosa to another location·View the California accessory structures overview
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ADU Impact Fees in Nearby Cities
How other cities in Sonoma County handle adu impact fees.