(a) An authority shall have no power to tax, but upon the adoption of the resolution by the governing body or bodies of participating units or subdivisions as provided in this article and the execution of a contract for the use of facilities and services of the authority by political subdivisions or participating units as authorized in Code Section 31-7-85, provision shall be made annually by such participating units or political subdivisions contracting with an authority for the payment for the services and facilities of the authority used by the participating units or subdivisions or the residents thereof out of general funds of the participating units or subdivisions or out of tax revenues realized for the purpose of providing medical care or hospitalization for the indigent sick and others entitled to the use of the services and facilities of the authority.

(b) For the purpose of providing such tax revenues as specified above, there is authorized to be levied an ad valorem tax not exceeding seven mills, exclusive of all other taxes which may be levied by counties or by cities or by towns, from which revenues when realized there shall be appropriated annually sums sufficient to pay for the cost of the use of the services and facilities of authorities by participating subdivisions or the residents thereof pursuant to the provisions and covenants of the contract between such participating units and subdivisions and authorities. In determining the cost of such services and facilities furnished pursuant to such contract, there may be included, but without limiting same, the following:

(1) The cost of acquiring, constructing, altering, repairing, renovating, improving, and equipping projects; and

(2) Principal, interest, and sinking fund and other reserve requirements in connection with the issuance of revenue certificates, bonds, or obligations by authorities to finance, in whole or in part, the cost of projects and the payment of expenses incident thereto; the cost of operating, maintaining, and repairing such projects; and the cost of retiring, refinancing, or refunding any outstanding debt or other obligation of any nature incurred by such authorities.

(c) Whenever the fiscal operations of any county falling within the classification of this chapter are governed by any statutory budget law applicable to the fiscal affairs and budget of such county, the governing authorities of such county shall have full power and authority hereunder to require the hospital authority to conform, in whole or in part, to the same budgetary procedures as are made binding by statute upon the county government itself.