A CR engineer running tests on a professionally installed water leak detector system
CR test engineer Richard Handel simulates leaks to test a professionally installed water leak detector system.

I’ll never forget the sound I heard when my wife and I returned home from a weekend trip last summer. It was as if there was a waterfall in our kitchen. In fact, there was: A supply line had burst, sending water rushing out of our cabinets, through the floorboards, and into the basement. It cost tens of thousands of dollars to fix all the water damage, but thankfully our homeowners insurance covered most of it.

Claims like ours are not uncommon. In 2018 alone, water damage and freezing accounted for nearly a quarter of all homeowners insurance losses, according to the Insurance Information Institute. The average claim from 2014 to 2018 was more than $10,000.

To prevent water damage, there is now a growing number of smart water leak detector systems that employ complex algorithms and sensors to alert you to leaks via a smartphone app (they all connect to your WiFi network) and automatically shut off your home’s water supply line.

More on Water Leaks and Cleanup

There are two main types of water leak detector: professionally installed models with a shutoff valve that is spliced right into your water line, and DIY models that sit on the quarter-turn valve on your water line and use a motor to open and close the valve automatically if a leak is detected.

We put five models to the test—three professionally installed systems and two DIY options. Ranging in price from $350 to $700, these systems are made by Flo by Moen, Guardian by Elexa, LeakSmart, Phyn, and StreamLabs. For the professionally installed systems, expect your cost to almost double when you factor in plumbing work. According to HomeAdvisor, it costs $375 to more than $600 to replace a main water-shutoff valve.

Below, you’ll find the details on the best professionally installed water leak detector system and the best DIY model from our tests. For the results of all the models, see our water leak detector system ratings


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The test engineer presses a button on the LeakSmart Whole House Snap Kit water shutoff unit.
DIY systems use a shutoff unit, such as this one from the LeakSmart Whole House Snap Kit, to rotate an existing quarter-turn water valve on and off.

How We Test Water Leak Detector Systems

In our tests, we focus on two key areas: leak detection and convenience.

We test both the professionally installed systems that detect leaks by monitoring water flow and pressure through the pipe and DIY systems that use wireless leak detectors—puck-sized, battery-powered devices with metal probes that detect the presence of water at the source of the leak. Put one in a cabinet under a sink, beneath the supply line to a toilet, or at the base of your water heater, and the smallest drop of water will activate the sensor. I personally now have six of these sensors scattered around my house—no more waterfalls for us, thanks. Some professional systems also make use of remote wireless sensors, as an added layer of protection.

For the professionally installed systems, our test engineers connect them to a water line and allow water to flow through them freely to test for large leaks. They also test for drip leaks by capping the end of the line and loosening it slightly to allow water to drip out. For the DIY systems, our engineers mount the shutoff unit onto a pipe with a quarter-turn valve and wet the probes on the leak sensors to simulate a leak, causing the sensors to send a wireless signal to the shutoff unit so that it turns off the water.

Our convenience test evaluates ease of installation and the features offered by the systems, such as whether they allow you to manually turn off the water, are weatherproof for water lines that are located outdoors, or offer battery backup (to keep the system up during a power outage).

“All of the detectors were able to detect simulated leaks, so we differentiated them based on the variety of ways they can detect leaks,” says Richard Handel, CR’s test engineer for water leak detector systems. “The best systems use both flow sensors, to detect large and small leaks in water supply pipes, and remote wireless leak detectors.”

Read on for detailed reviews of the two top-scoring systems in our tests, the Flo by Moen Smart Water Shutoff System and the Guardian by Elexa Leak Prevention System.

Best Professionally Installed Water Leak Detector System

Quick Take

Flo by Moen Smart Water Shutoff System 900-001

Price: $500

Leak detection
Convenience
Unlock Water Leak Detector Ratings

The Flo by Moen system is not only the best professionally installed system we tested but also the least expensive. The system consists only of the small shutoff unit that gets spliced into your water line; you can buy optional wireless leak sensors for $50 each, or $130 for three.

We tested the system with the optional detectors and, like the other professionally installed models, it was able to detect both small and large leaks. It receives an Excellent rating for leak detection because it comes with a flow sensor built into the shutoff valve unit, wireless leak sensors, and wire probes that can plug into the sensors and be run under a washer or water heater.

The Flo by Moen shutoff valve is weatherproof for homes in warmer climates where the water line might be located outdoors and above ground, but it lacks a built-in battery backup (you can buy one for $250). In addition to alerts for leaks, the Flo by Moen app can also track your water usage by fixture so that you can see the usage difference between, say, a long shower and your washer’s deep fill cycle. If you opt for the wireless leak detectors, you can also get temperature and humidity readings. 

Best DIY Water Leak Detector System

Quick Take

Guardian by Elexa Leak Prevention System GVD3

Price: $350

Leak detection
Convenience
Unlock Water Leak Detector Ratings

Because the Guardian by Elexa clamps onto your existing water valve instead of getting spliced into the water line, it detects leaks only via its three wireless leak detectors. But our tests show that it still performs well, with a rating of Very Good for leak detection since its detectors have probes underneath (for water on the floor) and on top (to catch drip leaks), as well as wire probes for hard-to-reach places.

It also scores well for convenience, thanks to its DIY installation and the fact that it has a button on the shutoff so that you can manually open and close the water valve without using its smartphone app.

In addition to leaks, the detectors sense temperature so that they can alert you to potential freezes. Additional leak detectors cost $70 each. An optional battery backup is also available for $29, but the shutoff is not weatherproof, meaning it won’t work for homes where the water line is located outside.

Because you have to install the Guardian system yourself, it’s important to make sure that you have enough clearance around the valve to clamp the shutoff unit onto the pipe. (I made the mistake of not measuring the space around my home’s water shutoff and had to return the DIY system I bought and start over.) You’ll need 4.5 inches of clearance on either side of the valve and 3.5 inches of clearance above the valve’s handle. You’ll also need a power outlet within 10 feet of the valve to power the system.