The continuous monitoring and real time analysis of chemical-physical parameters of freshwater flows is of fundamental importance for numerous strategic activities. For instance, the management of water resources, environmental monitoring and the study of chemical-physical and quantitative variations before and after major seismic events affecting areas where important aquifers are located. A low-cost and energy autonomous wireless sensing system has been developed for continuous water chemical-physical monitoring. In particular, the sensing system is capable of measuring the dissolved carbon dioxide (dCO 2 ) in water along with salinity, conductivity and temperature through a low-power (< 3 mW) infrared sensor.