Just like smoke detectors and sprinkler systems sense the presence of heat and smoke, water leak detectors work in a similar way through the presence of water, through electrical conductivity. Simply put, when the sensors come into contact with water, the ions in the water conduct electricity, alerting the sensors that there has been a leak, or moisture is nearby. This then triggers a signal through to the detector or your smartphone, and will either sound the built-in alarm, or create a notification on your smartphone.\r