A drip irrigation system consists of main lines, secondary lines, and lateral lines [1]. There are other important components such as filters, regulators of pressure, indicators of pressure, valves, injectors of fertilizer, and so forth. The lateral lines can be polyethylene tubes combined with drippers, or simply of low pressure plastic pipe with orifices. These are designed to distribute water to the field with an acceptable degree of uniformity [8, 9, 10]. The secondary line acts as a control system, which can adjust the pressure of water to supply the quantity of flow required in each lateral line. Also it is used to control the time of irrigation in individual field. The main line serves as a system of transportation to supply the total quantity of water required in the irrigation system. This chapter is a combined version of “Drip irrigation systems design” bulletins # 144 and 156 by the Coopertative Agricultural Extension Service at the University of Hawaii [11].