An irrigation controller and valves incorporating an irrigation controller, which have user allocatable identification numbers, is disclosed. The controller and valves are programmed when to operate according to their identification number, and the program is uploaded and stored in each controller or valve as the case may be, together with clock data. The controller and valves then perform time keeping and operate according to the stored program. The controller and valves are intended to be battery operated, obviating the need to install wiring to connect the valves back to a central controller. This allows simplified installation and programming, and provides improved flexibility in programming of irrigation.