Updated October 2026
Data from the official Flume and Third Reality sites.
2026 verdict
The Third Reality Water Leak Sensor is the one to choose if your home runs on Zigbee, and it is the cheaper and louder of the two.
It pairs in seconds with Home Assistant and Hubitat, sounds a 120 dB alarm that works even without a smart home connection, and includes a drip-sensor attachment. The Flume 2 Smart Water Monitor plays a different role: strapped to the water meter, it watches every drop the whole property uses with per-minute history, which no point sensor can do, and it needs no Zigbee hub. Pick the Third Reality Water Leak Sensor for local, loud leak alerts in a Zigbee home, and the Flume 2 Smart Water Monitor for whole-property leak and usage monitoring.
Works with
Connectivity
- Wi-Fi 2.4 GHz
vs
Winner
$20.99
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| Feature | Flume 2 Smart Water Monitor | Third Reality Water Leak Sensor | Winner |
|---|---|---|---|
| Rating | 4.0 | 4.1 | Third Reality Water Leak Sensor |
| Connectivity | 2.4 GHz WiFi, Other | Zigbee | Flume 2 Smart Water Monitor |
| Integrations | Google Home, Home Assistant | Google Home, Apple HomeKit, Samsung SmartThings, Home Assistant | Third Reality Water Leak Sensor |
| On Device Alert Sound | NO | YES | Third Reality Water Leak Sensor |
| Sensors | Water Leak | Water Leak | Tie |
| Alerts | Water Leak Alerts, Low Battery Alerts | Water Leak Alerts, Low Battery Alerts | Tie |
| On Device Alert Light | NO | NO | Tie |
What the differences mean
What it watches
The Flume 2 Smart Water Monitor reads the whole-house meter and sees every drop the property uses, including hidden leaks. The Third Reality Water Leak Sensor senses water only where its body sits.
Alarm
The Third Reality Water Leak Sensor sounds a 120 dB alarm from the unit that keeps working even if the hub is down. The Flume 2 Smart Water Monitor has no siren, so every alert arrives through the app.
Smart home fit
The Third Reality Water Leak Sensor pairs as a standard Zigbee device with SmartThings and Home Assistant. The Flume 2 Smart Water Monitor works with Google Home and Home Assistant, but is not a Zigbee device and needs its own bridge.
Installation
The Flume 2 Smart Water Monitor straps to an existing water meter with no plumbing, while the Third Reality Water Leak Sensor simply sits on the floor where water would reach it, with no meter compatibility to check.
Detection detail
The Third Reality Water Leak Sensor includes a drip-sensor attachment for slow leaks, and its sensing screws sit slightly raised, so a shallow puddle may need a spacer. The Flume 2 Smart Water Monitor measures flow at the meter instead.
Which one to buy if
- your smart home runs on Zigbee
The Third Reality Water Leak Sensor pairs as a standard Zigbee device with Home Assistant, Hubitat and SmartThings.
- you want a loud local alarm that survives a hub outage
The Third Reality Water Leak Sensor fires a 120 dB alarm at the unit, independent of the network.
- you want to catch leaks anywhere in the property
The Flume 2 Smart Water Monitor reads the whole-house meter, so it sees leaks that never reach a floor.
- you want detailed water usage data
The Flume 2 Smart Water Monitor reports usage per minute with history and budgets.
- you want a low-cost start with no meter check
The Third Reality Water Leak Sensor is cheaper and needs no meter compatibility list.
- + Connectivity: 2.4 GHz WiFi, Other
- - Rating: 4.0 vs 4.1
- - Integrations: Google Home, Home Assistant vs Google Home, Apple HomeKit, Samsung SmartThings, Home Assistant
Winner
$20.99
- + Rating: 4.1
- + Integrations: Google Home, Apple HomeKit, Samsung SmartThings, Home Assistant
- + On Device Alert Sound: YES
- - Connectivity: Zigbee vs 2.4 GHz WiFi, Other
What owners say
Both products earn the same kind of gratitude: owners describe a leak caught before it did damage. Third Reality Water Leak Sensor owners talk up the 120 dB alarm they can hear from another room, fast pairing with Home Assistant and Hubitat, and the value of running a dozen units; their caveats are that the sensing screws sit a little high, so shallow water may need a spacer or the drip attachment, and that a few units went offline or drained early after a year. Flume 2 Smart Water Monitor owners celebrate catching a seeping toilet flapper and the deep usage history, but dislike the proprietary replacement battery and the less-than-perfect per-fixture attribution.
Frequently Asked Questions
Which is better overall: Flume 2 Smart Water Monitor or Third Reality Water Leak Sensor?
They are not the same tool. The Third Reality Water Leak Sensor is the cheaper, louder point alarm built for Zigbee homes, while the Flume 2 Smart Water Monitor watches the whole property from the water meter and tracks usage, catching leaks no floor sensor reaches.
Does the Third Reality Water Leak Sensor need a hub?
Yes. It needs a Zigbee hub, and pairs with Home Assistant, Hubitat and SmartThings. The Flume 2 Smart Water Monitor needs no Zigbee hub and uses its own bridge.
Does the Flume 2 Smart Water Monitor have an alarm sound?
No. It is app-only. The Third Reality Water Leak Sensor has a 120 dB on-device alarm that works locally.
Which one can find a hidden leak?
The Flume 2 Smart Water Monitor, because it reads flow at the meter and sees leaks anywhere in the system. The Third Reality Water Leak Sensor only senses water that reaches its own body.
Can the Third Reality Water Leak Sensor detect slow drips?
Yes, it includes a drip-sensor attachment, and some buyers add small spacers under its raised sensing screws to catch shallow water. The Flume 2 Smart Water Monitor detects leaks through flow rather than contact.
Who should buy the Third Reality Water Leak Sensor?
Zigbee households that want a loud, reliable local alarm and cheap multi-sensor coverage under sinks and by washing machines.
Who should buy the Flume 2 Smart Water Monitor?
Owners who want whole-property leak detection and detailed water usage, can confirm meter compatibility, and do not need a siren.
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