605 ILCS 5/5-912
In order to minimize the effect of impact fees on the person paying the fees, the following methods of payment shall be used by the unit of local government in collecting impact fees. Impact fees imposed upon a residential development, consisting of one single family residence, shall be payable as a condition to the issuance of the building permit. Impact fees imposed upon all other types of new development, including multi-unit residential development, shall be payable as a condition to the issuance of the certificate of occupancy, provided that the developer and the unit of local government enter into an agreement designating that the developer notify the unit of local government that the building permit or the certificate of occupancy has been issued. For any development receiving assisted financing, including any development for which a commitment for assisted financing has been issued and for which assisted financing is provided within 6 months of the issuance of the certificate of occupancy, the unit of local government shall provide for the payment of the impact fees through an installment agreement at a reasonable rate of interest for a period of 10 years after the impact fee is due. Nothing contained in this Section shall preclude the payment of the impact fee at the time when the building permit is issued or at an earlier stage of development if agreed to by the unit of local government and the person paying the fees. Nothing contained in this Section shall preclude the unit of local government from making and entering into agreements providing for the cooperative collection of impact fees but the collection of impact fees shall be the sole responsibility of the unit of local government imposing the impact fee. Such agreements may also provide for the reimbursement of collection costs from the fees collected.
At the option of the unit of local government, impact fees may be paid through an installment agreement at a reasonable rate of interest for a period of up to 10 years after the impact fee is due.
Nothing contained in this section shall be construed to give units of local government a preference over the rights of any purchaser, mortgagee, judgment creditor or other lienholder arising prior to the filing in the office of the recorder of the county or counties in which the property is located of notification of the existence of any uncollected impact fees.
605 ILCS 5/5-912