65 ILCS 5/7-1-49

As provided in Section 8 of the Metropolitan Water Reclamation District Act, 60 days before the sale of any surplus real estate that is located in unincorporated territory and that is contiguous to only one municipality, the sanitary district shall notify in writing the contiguous municipality of the proposed sale. Before the sale of the real estate, the municipality shall notify in writing the sanitary district that the municipality will or will not annex the surplus real estate. If the contiguous municipality will annex such surplus real estate, then it shall be automatically annexed to the contiguous municipality coincident with the completion of the sale of that real estate by the sanitary district.