If you’ve ever come home to a soggy basement or found out too late that your kitchen sink or toilet has a slow leak, you know how expensive it can be to repair or replace carpets, flooring, and walls with water damage. Finding leaks before they cause major damage is now easier than ever thanks to water-sensing smart home devices that send alerts to your phone when they detect moisture. They range in complexity from simple puck-shaped sensors that you place on the floor to in-line systems that monitor your water flow rate for irregularities that might indicate leaks. At PCMag, we've been reviewing smart water sensors for nearly a decade. The $50 Flo by Moen is our Editors' Choice for its easy installation, responsive performance, and reasonable price. But it isn't the only model we recommend, so read on for all of our top picks.

What Is a Water Leak Detector?

The most basic DIY devices are battery-operated discs or small boxes that simply sit on the floor where leaks might occur, such as directly under a refrigerator, sink, toilet, or washing machine. They typically have two or more metal sensor terminals (feet) that are in contact with the floor, plus built-in Bluetooth or Wi-Fi radios to connect with your phone. The sensor triggers when the feet come in contact with water; typically just a few drops set it off. The device then sends a push alert or email (or both) and sounds an alarm. Make sure to look for a sensor that offers a reasonably loud siren that you can hear from anywhere in your home.

Of course, there’s always the possibility that leaking water begins to puddle in an area adjacent to the sensor’s location. To make sure that you get an alert before too much water accumulates, purchase a pack that comes with multiple sensors that enables you to expand the water detection range. Alternatively, purchase a sensor that comes with an extension cable. In most cases, the entire extension cable acts as a long, flexible sensor. You can hang this type of water sensor on a wall (with the cable resting on the floor) or place it directly on the floor along with the cable for maximum coverage.

(Credit: Orbit)

Although smaller, battery-powered sensors are great for detecting leaks in obvious places, they won’t tell you if there’s a leak in plumbing that resides behind your walls or in your ceiling. Granted, if water is leaking from a ceiling pipe, you’ll eventually find out. But by that time, you are likely dealing with damaged ceiling tiles and drywall, as well as possible wood rot. For whole-home protection, look for a leak detection system that monitors your entire water delivery system.

These types of systems usually need to operate in-line, in an area close to your water meter. They also likely require professional installation because they become a part of your plumbing system. As water flows through the device, it gathers information about your delivery system such as flow rate, pressure, and temperature. Once it learns the particulars of your home's water system over time (usually a week or two), it sends an alert if your water usage spikes or your water pressure changes, both of which may indicate a broken pipe or a faucet that has been left on. These devices can also tell you if you have a slow drip situation somewhere in your system and if your water temperature is too cold, a condition that can lead to burst pipes.

A handful of in-line smart monitors do more than just warn you of potential trouble: They generate daily, weekly, and monthly usage reports, plus tell you how much water each fixture (such as a shower, sink, or garden hose) uses. Additionally, they run system health tests periodically looking for abnormal pressure or flow rates. If they detect a problem, they automatically shut off the entire water supply to your home. These systems are ideal if you're frequently away from home or have a second home that remains empty for long stretches. 

What Makes a Leak Detector Smart?

A smart water sensor can communicate with your phone in several ways. Some sensors are Bluetooth-only, which means you must be within range of the device (typically 40 feet or so) to receive alerts and silence alarms. If you want to receive alerts and control the sensor while you’re away from home, make sure the device has a Wi-Fi radio or is part of a connected home automation system.

For anyone who lives in a climate where frozen pipes are a reality or where heat and humidity levels tend to run high, look for a water sensor that also monitors environmental conditions. If your sensor has built-in temperature and humidity sensors, it can send alerts when conditions reach a certain threshold. For example, if you live in a cold climate, you can set the sensor to alert you if the temperature drops to 32 degrees Fahrenheit, a level that can lead to burst pipes. Similarly, if you live in a hot climate with muggy conditions, you can configure the sensor to alert you when the humidity level hits 55% or higher to avoid mold growth. Abnormally high humidity levels can also indicate water leaks.

(Credit: Flume)

If you want your water sensor to do more than let you know that you have a leak, look for one that works with other smart devices. Alexa, Google Assistant, and Siri voice compatibility let you do things like silence alarms or check temperature and humidity levels simply by asking. Ideally, you want the sensor to trigger another device that can help minimize damage from the leak such as a fan or a dehumidifier, however.

Some water sensors are part of a family of smart devices from a single manufacturer that all work with the same app. If you choose a standalone sensor, make sure it supports IFTTT or is compatible with a home automation platform such as Alexa, Google Assistant, HomeKit, or SmartThings. With IFTTT, you can create applets that allow the sensor to trigger other compatible devices such as smart plugs and thermostats. Most home automation systems let you create automations or scenes to configure connected devices to work with each other.

How Much Does a Water Leak Detector Cost?

Smart water sensors cost anywhere from $50 to over $500. The more affordable models are just leak detectors that typically lack a Wi-Fi radio and communicate via Bluetooth or work as part of a home automation system. You pay more for features like environmental monitoring, extension cables, sirens, and LED indicators, as well as numerous integration options such as voice control and support for IFTTT. At the high end are the in-line systems that monitor your entire home and shut off your water if they detect a serious problem. Keep in mind that, in addition to a steep price, in-line systems require professional installation; that likely adds $200 or more to the total price.

For help getting started, see our story on how to set up your smart home.