Abstract: A remotely monitored tamper bar apparatus for monitoring two shut-off valve handles of a water supply backflow preventer includes an elongate U-shaped member having a base and two side legs. The base and two side legs form a channel for receiving the handles and to prevent movement of the handles. A switch is operatively associated with the U-shaped member. The switch has a first position which maintains the handles within the channel and a second position which allows the U-shaped member to be removed from the handles such that movement of the handles is permitted. The switch provides a signal for remotely monitoring whether the switch is in the first position or the second position.