Ga. Code § 47-1-41
A public employee may receive creditable service under the public employee's respective retirement system for a maximum of 12 months of temporary disability. A public employee wishing to obtain such creditable service shall apply to the board of trustees or other official or body administering the respective retirement system within not more than six months after returning to service immediately following the temporary disability. The public employee shall be required to pay the employee contributions that would have been paid during the period of temporary disability which is claimed for creditable service plus regular interest, as determined by the respective board of trustees or other official or body administering the respective retirement system, compounded from the period of disability for which creditable service is claimed to the date of payment. Such employee contribution shall be based on the compensation the public employee was receiving for employee contribution purposes immediately prior to becoming temporarily disabled.
OCGA § 47-1-41