55 ILCS 5/1-2005

No territory transferred under the provisions of this Division shall be released from the payment of its proportion of the debts of the county from which such territory is transferred; and such proportionate indebtedness from such transferred territory shall be collected by the county to which such territory is transferred, at an equal or greater rate than is levied and collected in the county from which such territory was transferred -- such rate to be ascertained by the certificate of the county clerk of said last named county, and when so collected, to be paid over to the county entitled thereto.