Nolen is a home handyman who has installed several types of water leak detectors and alarms in homes for his clients. What Are Water Leak Alarms? Undetected water leaks make up a large portion of the more than $20 billion in water damage that's caused to homes in the U.S. each year. A water leak detector or water alarm can help avoid costly damage to your home by alerting you to new leaks before they have a chance to do any harm.