Abstract: A gas-fired batch booster water heater for supplying sanitizing water to a dish washing machine comprises a chamber member, a water inlet tube, a gas-fired burner, a water outlet tube, a valve member, and a member for circulating water through the chamber member. The chamber member has a first opening operably attached to the water inlet tube and a second opening operably attached to the water outlet tube. The chamber member comprises an integrated heat exchanger and water tank. The gas-fired burner heats the water in the chamber member as it is circulated. The gas-fired batch booster water heater may further include a temperature sensor associated with the water inlet tube for controlling activation of the member for circulating water through the chamber member.