70 ILCS 605/5-1
The commissioners of a district may levy and collect assessments in the manner provided by this Article. Assessments shall be known and designated as "original assessments", "annual maintenance assessments" or "additional assessments". The designation "original assessment" shall apply only to the first assessment levied for the construction of the original work of the district and may include fees for the recording of documents as provided in this Act. The designation "annual maintenance assessment" shall apply only to assessments levied for the performance of the annual maintenance work of the district, including the purchase of necessary equipment and supplies to perform such annual maintenance work, the operation of pumping plants, to accumulate a contingency fund and to pay the current expenses of the district. The designation "additional assessment" shall apply to all assessments other than original assessments and annual maintenance assessments and shall include assessments for the completion of original, additional or repair work, the performance of additional or repair work, the construction, enlargement or repair of pumping plants, the payment of lawful obligations incurred by the district and for all other lawful purposes as set forth in this Act. No land or other property shall be assessed for benefits more than its just proportion of the entire assessment or in excess of the benefits thereto.
70 ILCS 605/5-1