A multizone irrigation system (230A) includes a central control unit (300)having a central control system (60) interfaced with a central valve (302) anda central communication unit (e.g., a pressure sensor 304). The central valveregulates water flow for irrigation from a water source and can lower waterpressure in the pipes using output (301). The central communication unit isconstructed to transmit or receive pressure based communication signalsproviding irrigation information. Each zone includes a sprinkler control unit(2311, 2312 ...231N) including a sprinkler connected to a water pipe forirrigation. Each sprinkler control unit includes a local controller (235)interfaced with a local valve (250) for controlling water flow to thesprinkler. The sprinkler control unit also includes a local communication unit(e.g., a pressure sensor 239) constructed to receive communication signalsfrom the central communication unit and provide received irrigationinformation to the local controller.
