Protect your home from expensive leaks and floods by installing a 3-Series Water Sensor near water heaters, drain pans, and underneath sinks. The Water Sensor is small, easy-to-use, and fits almost anywhere. Place the sensor directly on the ground and it will notify you when it detects the presence of water. Automatically shut off water supply to home in the event of a leak. Ensure that A/C drain pans don’t overflow.