A membrane-based, electrochemical sensor is being developed to signal the formation of corrosive conditions in low-conductivity environments (such as natural gas transportation lines). This sensor utilizes ion-conductive membranes, which respond to water content in the gaseous phase, as the conductive media for performing the electrochemical measurements. However, environments like natural gas pipelines may exhibit multiple phases during the sensor's use (i.e. natural gas, water, oils). The sensor, therefore, needs to be able to perform in a wide range of conditions for successful implementation in industrial uses. Here, we present conductivity data to demonstrate how an electrochemical sensor can be used to detect local changes in a multiphase system.