IL SB4062

Requires Illinois municipalities that levy impact fees on residential development to use standardized statewide formulas issued by the Department of Commerce and Economic Opportunity (DCEO), covering schools, parks, transportation, public safety, and stormwater facilities.

Mandates DCEO issue and annually update multipliers, capital cost tables, model worksheets/calculators, and a model ordinance that municipalities must adopt verbatim or with only technical deviations.

Allows municipalities to adopt fees lower than formula-derived maximums but prohibits exceeding those limits; middle housing must receive fee adjustments reflecting lower household size and service demand.

Exempts from impact fees: units affordable to households at 60% AMI, permanent supportive housing, transitional housing, and accessory dwelling units; optional reductions allowed for transit-oriented development and brownfield redevelopment.

Requires annual municipal reporting to DCEO on fees collected, expenditures, fund balances, and housing units approved; compliance with the new formula requirements becomes mandatory 30 months after the effective date.