Any municipal corporation initiating annexations under this article is authorized to make expenditures for surveys required to describe the property under consideration or for any other purpose necessary to plan for the study and annexation of unincorporated territory adjacent to the municipal corporation. In addition, following final passage of the annexation ordinance, the annexing municipal corporation shall have authority to proceed with expenditures for construction of water and sewer lines and other capital facilities and for any other purpose calculated to bring services into the annexed area in an effective and expeditious manner prior to the effective date of annexation.
OCGA § 36-36-60