Tennessee Code Title 7. Consolidated Governments and Local Governmental Functions and Entities § 7-51-402

(a) Counties, municipalities, utility districts, and cooperatives of this state billing and collecting user's fees, rates or charges for a utility service, including, but not limited to, water, sanitary sewer and electricity, or for garbage and refuse collection and disposal service, are authorized by resolution to enter into agreements with each other to provide for such billing and collection to be done by one for the other on such terms as may be agreed upon, including appropriate compensation. The county legislative body shall act for the county in making such agreements, except where billing and collection of such fees, rates or charges are performed by a board, commission or other agency of the county; provided, that such agreements entered into by a board, commission or other agency of the county shall be subject to approval by the county legislative body. The governing body of a municipality shall act for the municipality in making such agreements except where billing and collection of such fees, rates or charges are performed by a board, commission or other agency of the municipality; provided, that such agreements entered into by a board, commission or other agency of the municipality shall be subject to approval by the governing body of the municipality.

(b) Nothing in this section shall affect the authority of counties, county clerks, municipalities, utility districts and cooperatives to enter into agreements or contracts under any other statute or charter.