Ala. Const. art. XI, § 215.02

If the tax is authorized by vote of a majority of the qualified electors of the county who participate in any election called for that purpose, the governing body of every county except Mobile, Montgomery and Jefferson counties must levy and collect, in addition to all other taxes authorized by law, a special county tax, not exceeding four mills on each dollar of taxable property in the county to be used solely for acquiring, by purchase, lease, or otherwise, constructing, operating, equipping, or maintaining county hospitals, or other public hospitals, non-profit hospitals and public health facilities. An election may be called at any time by the governing body of the county, and must be called within three months of receipt of a petition, signed by not less than five percent of the qualified electors of the county, requesting that the election be called. The election shall be conducted in the manner which the governing body of the county prescribes.