Hayward, CA Accessory Structures: ADU Impact Fees (2026)

California state law - Government Code 65852.2(f)(3) - prohibits Hayward from charging any impact fees on an ADU under 750 sq ft. This exempts the unit from Hayward's Park Dedication / In-Lieu Fee, Transportation/Traffic Impact Fee, Public Facilities Impact Fee, and the Hayward Unified School District (HUSD) school facility fee. For ADUs 750 sq ft or larger, Hayward must charge impact fees proportional to the ratio of ADU floor area over primary dwelling floor area (Gov. Code 65852.2(f)(3)(B)). Hayward's standard building permit and plan-check fees still apply at any ADU size - typically $3,000-$8,000 for a detached unit - and are calculated on construction valuation per the Hayward Master Fee Schedule. East Bay Municipal Utility District (EBMUD) System Capacity Charges and East Bay Dischargers Authority sewer connection charges may apply but are subject to the same state ADU fee exemption when the unit is under 750 sq ft. HUSD school facility fees (collected under Education Code 17620 and SB 50) are waived for sub-750 sq ft ADUs by state preemption. The Mitigation Fee Act (Gov. Code 66020) lets a homeowner protest impact fees within 90 days of payment if they believe a fee was wrongly charged.