In counties with 3,000,000 or more inhabitants, the owner of property and the executor, administrator, or trustee of a decedent whose property has been omitted in the assessment in any year or years or on which a tax for which the property was liable has not been paid, and the several taxing bodies interested therein, shall be given at least 30 days notice in writing by the board of appeals (until the first Monday in December 1998 and the board of review beginning the first Monday in December 1998 and thereafter) or county assessor of the hearing on the proposed assessments of the omitted property. The board or assessor shall have full power to examine the owner, or the executor, administrator, trustee, legatee, or heirs of the decedent, or other person concerning the ownership, kind, character, amount and the value of the omitted property.
If the board determines that the property of any decedent was omitted from assessment during any year or years, or that a tax for which the property was liable, has not been paid, the board shall direct the county assessor to assess the property. However, if the county assessor, on his or her own initiative, makes such a determination, then the assessor shall assess the property. No charge for tax of previous years shall be made against any property prior to the date of ownership of the person owning the property at the time the liability for such omitted tax is first ascertained. Ownership as used in this Section refers to bona fide legal and equitable titles or interests acquired for value and without notice of the tax, as may appear by deed, deed of trust, mortgage, certificate of purchase or sale, or other form of contract. No such charge for tax of previous years shall be made against any property if:
The assessment of omitted property by the county assessor may be reviewed by the board in the same manner as other assessments are reviewed under the provisions of this Code and when so reviewed, the assessment shall not thereafter be subject to review by any succeeding board.
For the purpose of enforcing the provisions of this Code, relating to property omitted from assessment, the taxing bodies interested therein are hereby empowered to employ counsel to appear before the board or assessor (as the case may be) and take all necessary steps to enforce the assessment on the omitted property.
35 ILCS 200/16-135