305 ILCS 5/10-3
The Illinois Department shall establish a standard by which shall be measured the ability of responsible relatives to provide support, and shall implement the standard by rules governing its application. The standard and the rules shall take into account the buying and consumption patterns of self-supporting persons of modest income, present or future contingencies having direct bearing on maintenance of the relative's self-support status and fulfillment of his obligations to his immediate family, and any unusual or exceptional circumstances including estrangement or other personal or social factors, that have a bearing on family relationships and the relative's ability to meet his support obligations. The standard shall be recomputed periodically to reflect changes in the cost of living and other pertinent factors.
In addition to the standard, the Illinois Department may establish guidelines to be used exclusively to measure the ability of responsible relatives to provide support on behalf of applicants for or recipients of financial aid under Article IV of this Act and other persons who are given access to the child support enforcement services of this Article as provided in Section 10-1. In such case, the Illinois Department shall base the guidelines upon the applicable provisions of Sections 504, 505 and 505.2 of the Illinois Marriage and Dissolution of Marriage Act, as amended, and shall implement such guidelines by rules governing their application.
The term "administrative enforcement unit", when used in this Article, means local governmental units or the Child and Spouse Support Unit established under Section 10-3.1 when exercising the powers designated in this Article. The administrative enforcement unit shall apply the standard or guidelines, rules and procedures provided for by this Section and Sections 10-4 through 10-8 in determining the ability of responsible relatives to provide support for applicants for or recipients of financial aid under this Code, except that the administrative enforcement unit may apply such standard or guidelines, rules and procedures at its discretion with respect to those applicants for or recipients of financial aid under Article IV and other persons who are given access to the child support enforcement services of this Article as provided by Section 10-1.
305 ILCS 5/10-3