A low cost system and method for retrofitting an existing control device to communicate wirelessly with one or more water-flow devices is provided. For example, an existing wired irrigation system may be adapted to allow wireless communication between a commercially available irrigation controller and commercially available water-flow devices, such as sprinkler valves. A wireless irrigation adapter receives control signals from an existing irrigation controller and transmits a wireless representation of the control signals. Water-flow devices may be coupled to one or more wireless receivers that receive the wireless representation of the control signals and operate the water-flow device(s) accordingly. The wireless irrigation receiver(s) listen(s) for the wireless control signals occasionally, thus reducing power consumption by the wireless receiver(s). This system and method may also wirelessly adapt control devices to irrigation that may never have been intended for that purpose when they were fabricated.