ADU Impact Fees: Fairfield vs Vacaville

Is the water connection fee waived for a small ADU in Fairfield?

If the ADU shares the primary residence's existing water connection, no new connection fee can be charged. A new separate connection (rare for ADUs under 750 sq ft) would trigger the standard hookup charge from the relevant water utility.

Do I have to pay the Fairfield-Suisun school district fee for my 600 sq ft ADU?

No. School impact fees apply only to ADUs 500 sq ft or larger by state law, but Fairfield's practice and many ADU advocates note that even ADUs above 500 sq ft are sometimes waived; confirm with the school district facilities office before paying.

Are Vacaville ADUs charged impact fees?

ADUs under 750 sq ft are exempt from all city impact fees under California Government Code 66322(a) (formerly 65852.2(f)(3)). This includes Capital Facilities, Park, Traffic Impact, and Vacaville Unified School District facility fees. ADUs 750 sq ft and larger pay proportional fees based on size relative to the primary dwelling.

What does a Vacaville ADU cost to permit?

Permit and plan-check fees vary by valuation under Vacaville's Master Fee Schedule, typically $5,000-$10,000 for a detached ADU plus utility connection fees. Sub-750 sq ft ADUs are exempt from impact fees but still pay these permit fees plus PG&E electrical service upgrades and water/sewer connection charges through Vacaville Public Works Utilities.