O.C.G.A. § 36-71-11: Intergovernmental agreements.

Municipalities and counties which are jointly affected by development are authorized to enter into intergovernmental agreements with each other, with authorities, or with the state for the purpose of developing joint plans for capital improvements or for the purpose of agreeing to collect and expend development impact fees for system improvements, or both, provided that such agreement complies with any applicable state laws.