Ga. Code § 36-91-90
Payment bonds shall be required for all public works construction contracts subject to the requirements of this chapter with an estimated contract amount greater than $100,000.00; provided, however, that a governmental entity may require a payment bond for public works construction contracts that are estimated at $100,000.00 or less. No public works construction contract requiring a payment bond shall be valid for any purpose, unless the contractor shall give such payment bond; provided, however, that, in lieu of such payment bond, the governmental entity, in its discretion, may accept a cashier's check, certified check, or cash for the use and protection of all subcontractors and all persons supplying labor, materials, machinery, and equipment in the prosecution of work provided in the contract. The payment bond or other security accepted in lieu of a payment bond shall be in the amount of at least the total amount payable by the terms of the initial contract and shall be increased if requested by the governmental entity as the contract amount is increased.
OCGA § 36-91-90