The Cook County Assessor's Office serves the public both professionally and responsibly by establishing uniform and accurate property assessments. Assessed values are set on real estate as a basis for levying taxes and determining the distribution of property tax levies among taxpayers.


Administers the Valuation and Appeals Process in accordance with the State Property Tax Code (35 ILCS 200/) and the Cook County Code of Ordinances (Ordinance Chap. 74, Art. II, Div. 1, Sec. 74-31 et seq. and Div. 2, Sec. 74-60 et seq.).

Provides taxpayer assistance via the review, processing, and administration of exemptions through the State Property Tax Code Article 15.(35 ILCS 200/15).

Enforces the Erroneous Exemptions legislation (35 ILCS200/9-275) designed to target property owners who erroneously received property tax exemptions.

Key Activities and Services

  • Administers the Valuation and Appeals Process in Cook County by providing assessments, publicizing assessments, providing notices of increases, issuing certificates of correction, revising assessments, and providing valuations of particular types of property.
  • Assists taxpayers including Disabled Veterans, Returning Veterans, Disabled Persons, Senior Citizens, Long-time documents, and other taxpayers through the review, processing, and administration of property tax exemptions.
  • Responds to thousands of taxpayer inquiries and certificates of error.
  • Targets property owners who erroneously received property tax exemptions.
  • Provides permit/field operations services which generates and inspects permits for valuation purposes.
  • Develops wide reaching green and affordable housing programs through partnerships with different organizations.
  • Sponsors 145 community outreach seminars on the tax appeal process.

Discussion of 2017 Department and Program Outcomes 

The Assessor's Office is committed to completing the yearly assessment cycle as soon as possible in order to provide taxpayers the opportunity to receive their tax bills by the statutorily mandated dates.

Since 2014 the CCAO has been fully implementing enforcement of the Erroneous Exemption legislation. Through July 27, 2017, $25,654,925 have been recovered from erroneous exemptions and another $19,124,466 have been billed (of which liens amounting in $6,426,761 have been levied, drawing interest at 1.5% per month). There have been two favorable Appellate Court decisions in 2017 related to the Erroneous Exemption legislation: Cuevas v. Berrios, 2017 IL App (1st) 151318 and Mulry v. Berrios, 2017 IL App (1st) 152563.

The CCAO’s appeals process has been reinvigorated: Depending upon the triennial involved typically 13%-23% of all parcels appeal; 30-35% of residential filings have been on-line consistently since the 2012 reassessment and the trend continues for 2017 and 2018; There has been an increase in the appeals success rate for both residential and commercial property.

The CCAO is proactively working to create new tools and policies that will aid in the development of more affordable housing countywide. The CCAO is also actively involved in legislative efforts designed to stabilize the value of the Class 9 program (a current CCAO affordable housing incentive) and increase the number of affordable housing units in Cook County. In 2015, CCAO released its corresponding “White Paper” with continuing study in 2017-2018.

In 2017 the CCAO successfully advanced SB 473, to increase savings under the Homeowner and Senior Citizen Exemptions, as well as expanding eligibility for the Senior Freeze Exemption. The bill was approved by the Governor on 8/25/2017 and enacted as Public Act 100-0401.

Budget, Cost Analysis and 2018 Strategic Initiatives and Goals

The major cost drivers for the Office of the Assessor are the forthcoming City triennial assessment and $500,000 of GIS costs no longer reimbursed in FY18.

  • The Assessor’s Information Technology Department is leading the effort to successfully implement an Integrated Property Tax System (Tyler IasWorld – appraisal and tax solution) in collaboration with Tyler Technologies, the Assessor’s Office are business owners as well as the County Clerk, Treasurer, BOT and County GIS. For the 2018 Budget year we will be completing Fit/Gap, Configuration, Testing, and the majority of Training with a Rollout of the Tyler IasWorld system beginning in December of 2018 with the Assessor’s Office.
  • Improvement, update and modification of Industrial/Commercial worksheet program for analysts-several types and uses: Various commercial formats depending on property use, Apartment, Apartment/Commercial mixed use, Industrial, and Hotel/Motel.

Budget and Full Time Employee Data