55 ILCS 5/5-25020
Any county which has established a county health department or counties which have established a multiple-county health department may withdraw from a consolidated health department for the purpose of maintaining and operating an independent county or multiple-county health department, as the case may be, or for the purpose of joining with another adjacent county or other adjacent counties in maintaining and operating a consolidated health department. Withdrawal for such purposes may be effected by majority vote of the county board of the withdrawing county which had established a county health department, or by a majority vote of each county board of the withdrawing counties which had established a multiple-county health department, before joining the consolidated health department. In all withdrawals from consolidated health departments, the county board of each county proposing withdrawal shall seek the advice and concurrence of the Director of the Illinois Department of Public Health before taking action effecting withdrawal. The effective date of withdrawal shall be June 30 following completion of the withdrawal agreements. The board of health of the consolidated health department shall meet and the members of the withdrawing and the remaining counties shall agree upon removal of records, supplies, equipment and personnel by the withdrawing county or counties. Withdrawal of any county or counties from the consolidated health department does not alter the consolidation if the county or multiple-county health departments remaining party to the union are two or more. Discontinuance of any county or multiple-county health department effected under the provisions of Section 5-25017 constitutes withdrawal from a consolidated health department.
Any county which is a member county of a consolidated health department may also withdraw from the consolidated health department upon approval by referendum, the proposition for which shall be placed on the ballot at any general election by the county clerk on receipt of a petition signed by not less than 10 per cent of the registered voters of the county. The proposition shall be certified to the proper election officials, who shall submit the proposition to the voters at an election in accordance with the general election law. The proposition shall read substantially as follows:
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Shall .... county withdraw the county health department YES from the .................... ----------------------------------------------------- consolidated health department? NO
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If a majority of voters favor withdrawal the county shall arrange its withdrawal effective June 30 following the referendum and shall settle its affairs in the consolidated health department and resume operation in the manner hereinbefore prescribed in this section.
55 ILCS 5/5-25020