65 ILCS 5/11-111-10

Each lot, block, or part thereof, or tract of land in an improvement district specified in Section 11-111-8, whether already filled to grade or not, may be assessed to pay the cost of the improvement according to the special benefit it will receive therefrom.

When the ordinance under which the specified local improvement is ordered provides that the improvement shall be made wholly or partially by special taxation of contiguous property, the special tax shall be levied, assessed, and collected, as nearly as may be, in the manner provided by Article 9. However, no special tax shall be levied or assessed upon any property to pay for the improvement, in an amount in excess of the special benefit which that property will receive from the improvement. The ordinance is not conclusive of that benefit, but the question of that benefit and of the amount of the special tax are subject to court review, and shall be tried in the same manner as in proceedings by special assessment.