(750 ILCS 5/502) (from Ch. 40, par. 502)
    Sec. 502. Agreement.
    (a) To promote amicable settlement of disputes between parties to a marriage attendant upon the dissolution of their marriage, the parties may enter into an agreement containing provisions for disposition of any property owned by either of them, maintenance of either of them, support, parental responsibility allocation of their children, and support of their children as provided in Sections 513 and 513.5 after the children attain majority. The parties may also enter into an agreement allocating the sole or joint ownership of or responsibility for a companion animal. As used in this Section, "companion animal" does not include a service animal as defined in Section 2.01c of the Humane Care for Animals Act. Any agreement pursuant to this Section must be in writing, except for good cause shown with the approval of the court, before proceeding to an oral prove up.
    (b) The terms of the agreement, except those providing for the support and parental responsibility allocation of children, are binding upon the court unless it finds, after considering the economic circumstances of the parties and any other relevant evidence produced by the parties, on their own motion or on request of the court, that the agreement is unconscionable. The terms of the agreement incorporated into the judgment are binding if there is any conflict between the terms of the agreement and any testimony made at an uncontested prove-up hearing on the grounds or the substance of the agreement.
    (c) If the court finds the agreement unconscionable, it may request the parties to submit a revised agreement or upon hearing, may make orders for the disposition of property, maintenance, child support and other matters.
    (d) Unless the agreement provides to the contrary, its terms shall be set forth in the judgment, and the parties shall be ordered to perform under such terms, or if the agreement provides that its terms shall not be set forth in the judgment, the judgment shall identify the agreement and state that the court has approved its terms.
    (e) Terms of the agreement set forth in the judgment are enforceable by all remedies available for enforcement of a judgment, including contempt, and are enforceable as contract terms.
    (f) Child support, support of children as provided in Sections 513 and 513.5 after the children attain majority, and parental responsibility allocation of children may be modified upon a showing of a substantial change in circumstances. The parties may provide that maintenance is non-modifiable in amount, duration, or both. If the parties do not provide that maintenance is non-modifiable in amount, duration, or both, then those terms are modifiable upon a substantial change of circumstances. Property provisions of an agreement are never modifiable. The judgment may expressly preclude or limit modification of other terms set forth in the judgment if the agreement so provides. Otherwise, terms of an agreement set forth in the judgment are automatically modified by modification of the judgment.
(Source: P.A. 99-90, eff. 1-1-16; 99-763, eff. 1-1-17; 100-422, eff. 1-1-18.)