Dene Channell, Marion Rhodes, Titus Andrews, Sr., Gerald Torbert, and W.L. Sanders, in their capacity as members of the Greene County Board of Commissioners “Board”, appeal the trial court’s order granting to Chris Houston, in his capacity as Sheriff of Greene County “Houston”, relief in the form of a declaratory judgment that a special tax district established by the Board is unconstitutional, and enjoining the Board from implementing the special tax district. For the reasons that follow, we affirm. On March 17, 2009, the Board passed a resolution to create a special tax district to fund the Greene County Sheriff’s Office, with the district covering the entire county. Houston brought suit against the Board seeking, inter alia: a declaratory judgment that the establishment of such a special tax district was unconstitutional; a declaratory judgment that the Board’s separate “Fleet Management Policy” regarding Sheriff’s office vehicles was unconstitutional; that a writ of mandamus issue to require the Board to pay Houston’s previously authorized salary supplement; and that injunctions issue preventing the Board from implementing the special tax district and the “Fleet Management Policy,” and from further interfering with his duties. After a hearing, the superior court issued a declaratory judgment that the special tax district was unconstitutional, declared the resolution establishing it void, and enjoined the Board from implementing it. The court also ruled that the Board’s action regarding Houston’s salary supplement was legal, as the reduction would not take place during his then-current term of office, and that other prayers for relief were moot.1 We review de novo the trial court’s ruling that the Board’s resolution was unconstitutional. See Atlanta Oculoplastic Surgery, P.C. v. Nestlehutt et al. , 286 Ga. 731 691 SE2d 218 2010.
The power of county boards of commission in Georgia is not unlimited. Neither the counties of this state nor their officers can do any act, make any contract, nor incur any liability not authorized by some legislative act applicable thereto. If there is reasonable doubt of the existence of a particular power, the doubt is to be resolved in the negative. Powers of county commissioners are strictly limited by law, and they can do nothing except under authority of law. Mobley v. Polk County , 242 Ga. 798, 801-802 1 251 SE2d 538 1979 Citations omitted.. See also Boswell v. Bramlett , 274 Ga. 50, 52 2 549 SE2d 100 2001. As to the Board’s authority to create a special tax district, our State Constitution provides:
