Water leak and freeze detector, 3 sensors

More houses are damaged by water than by fire, and almost all of it starts somewhere nobody looks: behind a washing machine, under a sink, at a water heater that has been quietly weeping for a month, or in a pipe that froze while the house was empty.

Three remote probes on six-foot leads run to the three places that matter, with a 100 dB local alarm and a freeze alert that triggers at 41°F before the pipe reaches freezing. Battery powered with a low-battery signal, so there is nothing to wire.

Fitting and care. Put the probes flat on the floor at the lowest point near each risk, not against the appliance — water runs before it pools. The three that earn their place in most houses are behind the washing machine, under the kitchen sink and beside the water heater. Test each probe with a wet finger when you fit it. Change the batteries annually on the same weekend as the alarms. The freeze alert only helps if somebody is there to hear it, so pair it with a plan for when the house is empty.