Pros & Cons
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- Wide platform compatibility, including Matter
- Supports multiple wireless protocols
- Long battery life
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- Lacks a temperature sensor
Shelly Flood Gen4 Specs
| Product Category | Smart Home |
The best way to avoid water damage in your home is to catch leaks and floods early. The Shelly Flood Gen4 promises to send an alert whenever the sensor detects water from leaks or rainfall. It offers built-in Wi-Fi and supports Bluetooth and Zigbee wireless connectivity. It also supports Matter, which means it works with numerous smart home automation platforms, including Alexa, Google, HomeKit, and SmartThings. The Gen4 performed well in testing, and it comes at a very reasonable $32.99 price, so it earns our Editors’ Choice award for affordable smart leak detectors.
Design and Features: Expandable and Versatile
The Shelly Flood Gen4 Gen4 has an off-white rectangular enclosure with an IP44 waterproof rating, measuring 3.8 by 2.9 by 0.9 inches (HWD) and weighing 6.5 ounces with the batteries installed. It comes with four AA batteries that are rated to last up to two years before needing to be replaced. Also included are mounting screws, a 3.2-foot cable that connects the sensor to a 6.5-foot leak-sensing cord, an adhesive mounting pad, and a quick-start guide. If you have more space to monitor, you can pick up additional sensing cables and daisy-chain them for up to 490 feet of coverage.
(Credit: John R. Delaney)On the front of the sensor, you'll find an LED button that serves several functions. Tap it once to send the current sensor status to the mobile app, twice to put the sensor to sleep, three times to enter Zigbee mode, and five times to toggle back to the default Matter mode. You can press and hold the button for five seconds to reset network settings, and for 10 seconds to restore the sensor to its factory settings.
The LED turns blue when the sensor is ready for pairing, red when it's disconnected from the network, or yellow when it's connected to the network but disconnected from the cloud. When the sensor is connected to both, the LED turns green before going dark.
On the bottom edge of the Gen4, you'll find a port for the 3.2-foot connector cable; around back is a removable mounting plate for installing the sensor on a wall. You can access the battery compartment by prying the sensor open with a flathead screwdriver.
The sensor offers Flood Detection and Rain Detection modes. You use Flood mode to monitor common sources of leaks, like a washing machine or pipes under the sink; Rain, meanwhile, lets you automate outdoor devices such as automatic awnings and sprinkler systems. Flood mode also offers three alarm settings that change how the built-in buzzer performs. In Intense mode, it sounds continuously for 10 minutes, then for one minute every five minutes; in the default Normal mode, it sounds continuously for five minutes, then for one minute every half hour. Economic mode disables the buzzer, but the sensor still sends you push and email alerts.
If you want a sensor that can pair with a water shutoff valve, consider the First Alert L1 ($69.95). It costs more than twice as much as the Shelly Flood Gen4, but it can be paired with a Resideo (sold separately for around $200) to automatically shut off the water in your home when a leak is detected. The Flo by Moen ($49.99) is another model with this feature, but its companion water shutoff valve is more expensive at around $500.
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App and Integrations: Works With All Major Automation Platforms
The Gen4 uses Matter technology to integrate with many popular home automation platforms, including Alexa, HomeKit, Google, and SmartThings. It also has built-in Wi-Fi (2.4GHz), Zigbee, and Bluetooth radios, making it one of the most versatile water sensors I’ve come across. While it lacks some of the First Alert L1's big features—including temperature-sensing capabilities and the ability to trigger a water shutoff valve—the Gen4 will shut down appliances, such as washing machines, that are plugged into a smart outlet. The First Alert L1 and the Flo by Moen both omit third-party smart home platform integrations.
(Credit: Shelly/PCMag)The Gen4 uses the Shelly mobile app for iOS and Android mobile devices and appears in a panel on the app’s Dashboard screen. The panel displays the sensor's name, the room where it is installed, the battery level, and the current status (No for dry, Yes for water detected). Tap the panel to open a control screen for the sensor, where you can see the current status, configure settings, and view activity.
You get a ton of options: The Activity Log button takes you to a screen listing sensor events, and Notifications shows any unresolved events. Other buttons let you enable Flood or Rain mode, set up integrations with other Shelly smart devices (such as switches, plugs, and bulbs), configure the sensor's network settings, and turn on Bluetooth. A Settings button opens a screen where you can update the firmware, edit the sensor's name, perform a factory reset, or reboot the device.
Installation and Performance: Fuss-Free Peace of Mind
Installing the Gen4 is easy. Using a flathead screwdriver, I popped open the battery compartment and pulled the tab to activate the batteries, then downloaded the mobile app and created an account. Then came a bit of screen-tapping—first Add Device on the All Devices screen, then Add via Bluetooth—after which I pressed the LED button on the sensor. The indicator turned blue, and the app immediately discovered the sensor. When prompted, I entered my Wi-Fi credentials, tapped Add Device, and the sensor was added to the Shelly cloud and to the app. I gave the sensor a name, added it to a room, and the pairing was complete.
(Credit: John R. Delaney)As luck would have it, I haven't had any water-leak issues anywhere in my house recently, so I tested the Gen4 in my kitchen sink, placing the sensor on my countertop and the sensor cable in the (dry) sink. When I sprinkled a drop or two of water over the cable, the sensor immediately began emitting a loud beeping sound, and I instantly received an email notification and a push alert. The Shelly app, meanwhile, generated a loud alarm through my phone. Results were the same when the cable was immersed in a pool of water.
I had no trouble using the Matter code to add the Gen4 to my Apple Home app and to my Alexa app. What's more, an automation I created using Apple Home worked perfectly, turning a TP-Link L535E smart bulb red when the Gen4 sensor detected water. An Alexa routine I set up to have a TP-Link P110M smart plug turn off when water was detected also worked reliably.