Abstract: An irrigation system includes an elongate pipe having a plurality of water discharge ports spaced along its length. Each port is individually adjustable, such as by means of a collar about the pipe, to deliver water in a straight stream, spray, trickle, drip, or to be closed completely so that no water is delivered through a particular port. The system is preferably made up of a number of individual lengths of pipe adapted to be easily joined together to give the desired total length.