Updated October 2026
Data from Amazon and official Shelly site.
2026 verdict
Same name, very different radios: the Shelly Flood Gen4 is the Shelly water leak sensor to buy, adding Zigbee, Bluetooth and Matter to the Wi-Fi the original relied on.
It also adds a buzzer and an LED for local alerts, a 2 m extendable sensing cable, Apple Home and SmartThings through Matter, an IP44 rating, 2 years on four AA cells and a 3-year warranty. The Shelly Flood keeps two things going for it: it is the lower priced of the two and a much smaller, lighter puck. Both measure temperature and send freeze alerts, and both work with Google Home and Home Assistant. Choose the Shelly Flood Gen4 for a new install, and keep the Shelly Flood only if you want a cheap, compact Wi-Fi sensor and do not need a siren.
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| Feature | Shelly Flood | Shelly Flood Gen4 | Winner |
|---|---|---|---|
| Rating | 3.8 | 4.2 | Shelly Flood Gen4 |
| Warranty | 2 years | 3 years | Shelly Flood Gen4 |
| Battery Life | 1.5 years | 2 years | Shelly Flood Gen4 |
| Connectivity | 2.4 GHz WiFi | 2.4 GHz WiFi, Bluetooth, Zigbee | Shelly Flood Gen4 |
| Integrations | Google Home, Samsung SmartThings, Home Assistant | Google Home, Apple HomeKit, Samsung SmartThings, Home Assistant, Matter | Shelly Flood Gen4 |
| On Device Alert Sound | NO | YES | Shelly Flood Gen4 |
| On Device Alert Light | NO | YES | Shelly Flood Gen4 |
| Sensors | Water Leak, Temperature | Water Leak, Temperature | Tie |
| Alerts | Water Leak Alerts, Temperature Alerts, Freeze Temperature Alerts, Low Battery Alerts | Water Leak Alerts, Temperature Alerts, Freeze Temperature Alerts, Low Battery Alerts | Tie |
What the differences mean
Radios
The Shelly Flood is Wi-Fi only. The Shelly Flood Gen4 adds Zigbee, Bluetooth and Matter, so it can join a Zigbee network where it sips less power and, through Matter, reach Apple Home and SmartThings.
Local alarm
The Shelly Flood Gen4 has a built-in buzzer and an LED, so a leak is heard in the room. The Shelly Flood has neither and only alerts through the app and your smart home.
Sensing cable
The Shelly Flood Gen4 ships with a 2 m extendable sensing cable that reaches under cabinets and into crawlspaces. The Shelly Flood only senses water right under its own puck.
Size and batteries
The Shelly Flood is a 70 x 70 x 19 mm puck of about 26 g on one CR123A cell, not included. The Shelly Flood Gen4 is a bigger 97 x 76 x 25 mm, 91 g box on four AA cells, rated 2 years against 1.5.
Warranty
Shelly covers the Shelly Flood Gen4 for 3 years and the Shelly Flood for 2, a small but real extra year for a sensor meant to sit untouched.
Which one to buy if
- your home runs on Apple Home or Matter
Only the Shelly Flood Gen4 supports Matter, which is how it reaches Apple Home and SmartThings.
- you want to hear the alarm in the house
The Shelly Flood Gen4 has a buzzer and LED; the Shelly Flood is silent.
- the leak point is hard to reach, like the back of a cabinet
The 2 m extendable sensing cable of the Shelly Flood Gen4 reaches where a puck cannot sit.
- you want the cheapest, smallest Wi-Fi sensor for several spots
The Shelly Flood is the lower priced and much smaller of the two, and still reports temperature.
- - Rating: 3.8 vs 4.2
- - Warranty: 2 years vs 3 years
Winner
$39.99
- + Rating: 4.2
- + Warranty: 3 years
- + Battery Life: 2 years
What owners say
Owners of both Shelly sensors describe the same kind of buyer: Home Assistant users who like that the sensor shows up with little effort, and both groups mention Wi-Fi onboarding that can take a few attempts. Shelly Flood owners like setting it up from a phone browser with no app, the temperature readings they get for free and a price that lets them put one by every water source; their main complaint is units that drop off Wi-Fi and need reconnecting. Shelly Flood Gen4 owners single out stable, fast pairing over Zigbee, a cable sensitive enough to catch a single drop, the buzzer and LED, and on-device automations that switch off other Shelly devices, while a few who paired it over Matter into Apple Home say the leak status did not refresh without a button press.
Upgrading from the Shelly Flood?
Moving up from the Shelly Flood to the Shelly Flood Gen4 buys three things: a buzzer and LED that alert in the room, a 2 m sensing cable, and Zigbee, Bluetooth and Matter next to Wi-Fi, which opens Apple Home and SmartThings. The battery also lasts longer and the warranty is a year longer. If your Shelly Flood sits in Home Assistant, stays connected and you only need app alerts, there is little reason to replace it.
Price history compared
Every price change of both, in the same store, so the gap between the two lines is what one costs more than the other.
- Shelly Flood
- Shelly Flood Gen4
Loading price history...
Frequently Asked Questions
Which is better overall: Shelly Flood or Shelly Flood Gen4?
The Shelly Flood Gen4. It adds Zigbee, Bluetooth and Matter, a buzzer and LED, a 2 m sensing cable, a longer battery life and a 3-year warranty. The Shelly Flood is smaller and cheaper but Wi-Fi only and silent.
What is the difference between the Shelly Flood and the Shelly Flood Gen4?
The Shelly Flood Gen4 is a multi-protocol sensor with Wi-Fi, Zigbee, Bluetooth and Matter, a local buzzer and an included sensing cable. The Shelly Flood is a Wi-Fi only puck with no siren. Both sense temperature and send freeze alerts.
What is the battery life of the Shelly Flood Gen4?
The Shelly Flood Gen4 is rated for about 2 years on four AA batteries. The older Shelly Flood is rated for about 1.5 years on a single CR123A cell, which is not included in the box.
Do the Shelly Flood and the Shelly Flood Gen4 work with Apple Home?
Only the Shelly Flood Gen4, through Matter, which also brings SmartThings. The Shelly Flood has no Apple Home or Matter support, though both work with Google Home and Home Assistant.
Who should buy the Shelly Flood?
Home Assistant and Google Home users who want a small, inexpensive Wi-Fi leak and temperature sensor for many spots and are fine with app alerts only.
Who should buy the Shelly Flood Gen4?
Anyone setting up leak detection today who wants a local alarm, a sensing cable and the choice of Wi-Fi, Zigbee or Matter, including Apple Home households.
Full comparison table
Compare all 34 Water Leak Sensors side by side
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