Shelly
Flood
Shelly Flood is a battery-powered Wi-Fi water leak sensor that fires the moment its contacts detect water, and also reports ambient temperature for early freeze warnings.
Protocols
Roles it can fill
Sits at the lowest point under sinks, water heaters, and washing machines, and also reports temperature for freeze alerts. Local alerts through the native Shelly integration keep working when the internet is down, which matters most for an emergency sensor. Also speaks MQTT.