Impact Fees

One-time fees charged by cities to fund infrastructure (roads, schools, water, sewer) impacted by new development.

Why it matters

California state law (SB-13, 2019) waives impact fees for ADUs under 750 sqft. ADUs over 750 sqft pay proportional impact fees, typically $4-$30 per sqft. School impact fees are waived under 750 sqft and charged proportionally above.

Related terms

• SB-13
• Building Permit

See also

• Permit fees breakdown

Part of the BackyardADU California ADU Glossary — plain-English definitions of the regulatory, construction, and financing terms you'll encounter during a California ADU project.