A water leak sensor with its own 90dB alarm on board for water heaters, laundry pans, sump pits and under sink cabinets. Reports to Home Assistant through a Tapo hub.
Two alarms, in two places, and it is worth knowing which is which. The sensor carries its own 90dB siren, adjustable and silenced with one touch at the unit, and it sounds the moment its probes bridge, which is what protects a floor when nobody is watching a dashboard. It can also trigger the alarm in the hub, so a leak under a basement laundry can be heard upstairs. The leak itself reports to Home Assistant through an H100 or H200 hub over sub-1GHz. Home Assistant gets the moisture binary sensor and battery through the tplink integration, so a recipe can cut a smart valve or a pump circuit and notify at the same time. Site it at the lowest point where water will actually collect rather than beside the appliance, and test it with a wet finger after mounting.