65 ILCS 5/11-85-3
If a municipality desires to pay its proportion of the cost of such an improvement by a special assessment or a special tax upon the property within the municipality benefited by the improvement, either before or after the letting of the contract as provided by Section 11-85-2, it may pass an ordinance providing for the improvement and that the cost thereof shall be paid by a special tax or a special assessment, to be levied upon the municipality and upon the property within the municipality specially benefited by the improvement. The proceedings thereafter for the levy of that special assessment or special tax, and the collection thereof, shall conform to the provisions of Article 9, in so far as the provisions of Article 9 are applicable. It shall be no defense in any proceedings to levy a special assessment or a special tax hereunder that the special assessment or special tax is levied for work previously performed.
65 ILCS 5/11-85-3