Thousand Oaks, CA Accessory Structures: ADU Impact Fees (2026)
Key Facts
- Impact fee exemption
- ADUs under 750 sq ft
- ADUs 750 sq ft or larger
- Fee proportionate to primary dwelling's square footage
- New utility connection fee
- Only if built with a new single-family dwelling
Summary
ADUs under 750 square feet are exempt from local impact fees in Thousand Oaks, and an ADU generally isn't treated as a "new residential use" for utility connection fees or capacity charges unless it's built together with a brand-new single-family home.
(a) An ADU/JADU may not be considered a new residential use by a local agency, special district, or water corporation to calculate utility connection fees or capacity charges unless the ADU is constructed with a new single-family dwelling.
(b) Impact fees may not be assessed by local agencies, special districts, or water corporations on an ADU smaller than 750 square feet. Impact fees may be assessed on an ADU of 750 square feet or greater in an amount proportionate to the square footage of the primary dwelling unit.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-78: 2026 S-78 Supplement contains: Current city legislation passed through March 31, 2026).
Full Breakdown
Once an ADU reaches 750 square feet or larger, impact fees can be charged, but only in proportion to the ADU's square footage relative to the primary dwelling, not the full fee schedule that applies to a new single-family home. Utility connection and capacity charges follow the same logic: an ADU built as a stand-alone addition to an existing home isn't billed as a brand-new residential connection.
Violations & Fines
Not applicable: this section restricts what fees local agencies may charge homeowners rather than imposing an obligation on residents.
Frequently Asked Questions
Will I be charged school or park impact fees for a small ADU?
Do I need a brand-new water meter for my ADU?
Sources & Official References
Other rules in Thousand Oaks
California rules heatmap·Compare Thousand Oaks to another location·View the California accessory structures overview
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ADU Impact Fees in Nearby Cities
How other cities in Ventura County handle adu impact fees.