IL HB1287

Requires owners of income-producing properties in Cook County (3,000,000+ inhabitants) to file physical descriptions of their properties with the chief county assessor; other counties may opt in by ordinance or resolution

Property owners must file within 120 days of the Act's effective date and update filings within 120 days of any material change to the physical description

Exempts properties valued at $500,000 or less, residential properties with 6 or fewer units, hospitals, nursing homes, state-assessed railroad/utility properties, and large stadiums hosting major professional sports

Non-compliant owners face penalties up to 0.025% of the property's prior year market value, capped at $1,000 per property, with interest of 0.05% per month accruing after unsuccessful appeals

Physical descriptions must include land size, construction type, year built, development size, and property-type-specific details (unit counts for multi-family, net rentable area for office/retail, dock sizes for industrial, room counts for hotels)