Kidde knows a thing or two about keeping your home safe. Their smoke alarms have been a reliable presence in homes for decades. This WiFi water leak detector does something similar for the parts of your house you don’t always see. It catches pinhole leaks under sinks, a slow drip from a refrigerator line, or a washing machine hose failure before that water finds your floorboards.

The sensor is about the size of a hockey puck. Place it on the floor near a water heater or behind a toilet. When water touches the two metal prongs on the bottom, the app sends a push alert to your phone immediately. It also monitors for freezing temperatures, which is useful for garages or basements where pipes are vulnerable. The device runs on a single CR123 battery, and the app shows the remaining battery level so you aren’t caught off guard.

It works with both Amazon Alexa and Google Assistant. You can set up routines, like having a smart light turn red when a leak is detected. The main limitation is that it requires a stable 2.4GHz WiFi connection. If your router is far from the installation spot, the signal may drop. For $35, this is a straightforward early warning system that saves you from discovering a problem by stepping in a puddle.