Avoid a Big Water-Damage Bill With $20 Leak Sensors

The problem

Most water damage starts small: a washer hose that weeps, a dishwasher seal that drips, an ice maker line that lets go, a water heater that slowly gives out. Nobody notices until the cabinet floor is soft, the hardwood is cupped or there's a stain on the ceiling below.

By then it's expensive. Industry figures put the average homeowner's water damage claim at well over $12,000 (ConsumerAffairs, from Insurance Information Institute data), and that's before the hassle of fans, contractors and an insurance claim. A leak caught in the first few minutes is usually just a towel and a wet floor.

What you need

• Water leak sensors. Small, battery-powered pucks that sit on the floor and alert the moment water touches their contacts. They're cheap enough to put one at every spot that worries you, and they're usually sold singly or in multi-packs that cost less per sensor.
• A hub that the sensors talk to wirelessly. It plugs into the wall, connects to your Wi-Fi and sends alerts to an app on your phone. Most hubs can also sound an alarm at home.
• Wi-Fi where the hub sits. Many hubs only use the 2.4 GHz band, which most home routers provide.

How it works

Put a sensor flat on the floor wherever a leak would start. The moment water touches it, the hub knows. Within seconds you get an alert on your phone naming which sensor it is, and the hub can sound an alarm so anyone at home hears it too.

Good places for a sensor:

• Under each sink, kitchen and bathrooms
• Under or beside the dishwasher
• Behind the clothes washer
• By the refrigerator, if it has an ice maker or water line
• Next to the water heater
• Behind toilets, if that's a worry
• Near the sump pump or anywhere water tends to show up first

They've earned their keep at my house. They caught a leaking clothes washer, and a refrigerator ice maker that started melting and dripping in an odd way. Both were wiped up before they did any damage. And one memorable false alarm: our dog picked a sensor up and carried it off, which set it off. So it works.

Dead-battery warnings: the hub also notices when a sensor stops checking in, and tells you. A sensor with a dead battery is worse than no sensor, because you'd assume it's watching. With this, you know right away that a sensor needs attention.

Setting it up

1. Plug in the hub somewhere central, set it up in its app and connect it to your Wi-Fi.
2. Add each sensor in the app, following the maker's pairing steps.
3. Name each sensor by its spot, like "Kitchen sink" or "Washer". The alert uses that name, so you know exactly where to go.
4. Place them flat on the floor, with the contacts touching the surface, where water would collect first.
5. Turn on notifications for the app, and turn on the hub's alarm sound if you want one at home.
6. Test each one: touch it with a damp paper towel, or set it on a wet cloth. Confirm the alert names the right sensor.

Upkeep

• Batteries: mine are rated for about two years, and in my experience they last a long time, but I replace them every year just to be safe. Check the sensor or manual for the battery type.
• Pay attention to "offline" alerts. That usually means a dead battery or a sensor that's been moved out of range.
• Test them once or twice a year, for example when you change the batteries.
• Put them back after cleaning under the sink. It's easy to forget one in a drawer.

What it doesn't fix

• It doesn't stop the water. It tells you to go turn off the valve. Automatic shutoff valves exist, but that's a bigger project.
• Alerts need the hub, power and internet. If you're away, pair this with rock-solid internet so the hub stays online.
• It only catches water that reaches a sensor. A leak inside a wall or ceiling may not show up where a sensor sits.
• It's not a replacement for maintenance. Replace old washer and dishwasher hoses, and keep an eye on an aging water heater.

If you're starting with one or two: put them where mine have actually caught water, behind the clothes washer and by the refrigerator.

Products named here are ones I bought and use myself. No sponsorships, no affiliate links.
I'm not a licensed electrician or other professional. Follow the product instructions and local codes, and call a qualified pro if you're unsure. Full disclaimer.