The irrigation water quality, as well as the correct management of the water resources, is essential for the productivity and efficiency of the crops. Controlling and analyzing water before irrigating is crucial and its quality may vary significantly depending on the time of year. So frequent measurements are recommended. The Spanish company GMV has developed a water quality monitoring system based in Libelium technology. The nodes were installed at the El Portal irrigation dam, located on the Guadalete river where it passes through Jerez de la Frontera (Spain).