A water measuring system for measuring different parameters of water having a compact configuration that can be easily calibrated is provided. A plurality of individual sensors, are mounted on the housing, including a dissolved oxygen measuring sensor that can be mounted at a position separate from the other sensors. A hood member can be mounted at the lower end of the housing member to protect the sensors. A container that is capable of holding a calibration liquid can be fitted onto the housing member to provide the liquid at a position that will only contact those sensors other than the oxygen measuring sensor during a single calibration procedure.