Most homeowners are eligible for this exemption if they own and occupy their property as their principal place of residence. This exemption lasts up to four years.Application Due Date: No application is required. For information and to apply for this homestead exemption, contact the Cook County Assessor's Office. Senior Citizen Homestead Exemption. Link to obtain further information about the various exemptions that are offered, the documents and filing process required for each exemption to be claimed. The BOR accepts exemption applications for approximately 30 days, four times each year. You can apply online for any of these exemptions through the Cook County Assessor's Office. Join us for a workshop to learn about the Cook County Assessor's Office and homeowner exemptions. The deadline for homeowners to apply for current property tax exemptions (tax year 2021) is Friday, August 26, 2022.