If the department, in carrying out Code Section 12-5-70, shall encounter water in sufficient quantities to be useful to any municipality or county in furnishing water to its inhabitants, the department may contract with such municipality for the use of such water, and, in so doing, may sell or lease any such well or water supply, provided that no such lease shall be for longer than 30 years. Such contract, whether in the form of a lease contract or a sales contract, shall be subject to approval as to form by the Attorney General.
OCGA § 12-5-72