ADU Impact Fees: Mountain View vs Sunnyvale
How do adu impact fees rules compare between Mountain View, CA and Sunnyvale, CA?
Mountain View, CA
Santa Clara County
No data available yet for Mountain View.
Sunnyvale, CA
Santa Clara County
Under California Government Code 65852.2(f)(3), Sunnyvale ADUs under 750 square feet are exempt from all city impact fees. ADUs 750 square feet or larger pay impact fees proportional to the primary dwelling. Sunnyvale's own permit and plan-check fees are moderate by Silicon Valley standards.
View full Sunnyvale rules →Key Facts Comparison
| Fact | Mountain View | Sunnyvale |
|---|---|---|
| Authority | - | Gov. Code 65852.2(f)(3) |
| Sub-750 sq ft ADU | - | Exempt from all city impact fees |
| 750+ sq ft ADU | - | Proportional impact fees |
| Permit/Plan Check | - | ~$3,000-$6,000 (any size) |
| School Fees Authority | - | Ed. Code 17620 (~$5.17/sq ft) |
| BMR Trigger | - | 5+ units (not single ADU) |
Highlighted rows indicate differences between cities.
Mountain View FAQ
No FAQs available.
Sunnyvale FAQ
Are Sunnyvale ADUs charged impact fees?
ADUs under 750 sq ft are exempt from all city impact fees under California Government Code 65852.2(f)(3). This includes Sunnyvale park, traffic, and capital facilities fees as well as school impact fees. ADUs 750 sq ft and larger pay fees proportional to the primary dwelling's size.
What does a Sunnyvale ADU cost to permit?
Permit and plan-check fees typically run $3,000-$6,000 - moderate among Silicon Valley cities. ADUs under 750 sq ft skip all impact fees under state law. ADUs over 750 sq ft pay proportional impact and school fees on top of the permit cost.
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