Water Leak Sensors · Head to head

eufy Security Flood & Freeze Sensor E20 vs Third Reality Water Leak Sensor

Full Smart Water Leak Sensors comparison in 2026

Updated October 2026
Data from the official Eufy and Third Reality sites.
2026 verdict
Battery life and freeze coverage settle this one for the eufy Security Flood & Freeze Sensor E20 over the Third Reality Water Leak Sensor.
eufy Security Flood & Freeze Sensor E20
Winner
eufy Security Flood & Freeze Sensor E20
$39.99
Buy on Amazon USA
The E20 runs five years on a CR123A against three on the Third Reality, warns on freezing pipes as well as water, and ships a 1.2 m probe plus a 75 dB buzzer with a red LED. The Third Reality Water Leak Sensor is the cheaper unit and the better connected one, pairing over Zigbee with SmartThings and Home Assistant and reaching Google Home or Apple HomeKit through the Smart Bridge MZ1, and its 120 dB alarm is the louder of the two. The eufy Security Flood & Freeze Sensor E20 needs a Eufy HomeBase and lives mostly inside that app. Pick the eufy Security Flood & Freeze Sensor E20 for a Eufy home that wants freeze alerts and a long battery, and the Third Reality Water Leak Sensor for a loud, cheap alarm on a Zigbee hub.
vs
Third Reality Water Leak Sensor
Third Reality

Third Reality Water Leak Sensor

Prime exclusive deal
$20.99
Buy on Amazon USA

Also sold in packs

  • Pack of 2$39.99$20.00 per unitYou save $1.99Buy
  • Pack of 4$79.99$20.00 per unitYou save $3.97Buy
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Featureeufy Security Flood & Freeze Sensor E20Third Reality Water Leak SensorWinner
Price$39.99$20.99Third Reality Water Leak Sensor
Rating4.24.1eufy Security Flood & Freeze Sensor E20
Battery Life5 years3 yearseufy Security Flood & Freeze Sensor E20
IntegrationsHome AssistantGoogle Home, Apple HomeKit, Samsung SmartThings, Home AssistantThird Reality Water Leak Sensor
SensorsWater Leak, TemperatureWater Leakeufy Security Flood & Freeze Sensor E20
AlertsWater Leak Alerts, Freeze Temperature Alerts, Low Battery AlertsWater Leak Alerts, Low Battery Alertseufy Security Flood & Freeze Sensor E20
On Device Alert LightYESNOeufy Security Flood & Freeze Sensor E20
Connectivity2.4 GHz WiFiZigbeeTie
On Device Alert SoundYESYESTie

What the differences mean

Freeze detection

The eufy Security Flood & Freeze Sensor E20 warns on freezing pipes as well as water, with several thresholds set in the app. The Third Reality Water Leak Sensor is water only, so a cold snap near the same pipe is invisible to it.

How it connects

The eufy Security Flood & Freeze Sensor E20 needs a US Eufy HomeBase and reports through the Eufy app. The Third Reality Water Leak Sensor needs a Zigbee hub, which can be a SmartThings unit, a Home Assistant coordinator or a Hubitat.

Alarm

The Third Reality Water Leak Sensor sounds a 120 dB alarm, the louder of the two, but has no indicator light. The eufy Security Flood & Freeze Sensor E20 uses a 75 dB buzzer with a red LED, so you can also see which unit is going off.

Battery

The eufy Security Flood & Freeze Sensor E20 is rated for five years on a CR123A, while the Third Reality Water Leak Sensor runs on two AAA cells rated for about three. Both are long enough to place and forget, but the E20 asks for fewer changes.

Integrations

The Third Reality Water Leak Sensor works with SmartThings and Home Assistant directly, plus Google Home and Apple HomeKit through the Smart Bridge MZ1. The eufy Security Flood & Freeze Sensor E20 reaches Home Assistant through a community integration only.

Probe and placement

The eufy Security Flood & Freeze Sensor E20 includes a thin 1.2 m probe for the space under an appliance. The Third Reality Water Leak Sensor instead ships a drip-sensor attachment, since its own body has to sit where the water arrives.

Which one to buy if

What owners say

The Third Reality Water Leak Sensor has the owner history here, and the 120 dB alarm dominates what they say: buyers describe hearing it from another room or floor, and they value that it works even when the smart home connection is down. Pairing on Home Assistant, Hubitat and Zigbee2MQTT comes up as fast and trouble-free, and many owners run a dozen or more units for whole-house coverage. The complaints are specific. The sensing screws sit slightly raised, so a few buyers add spacers or the included drip-sensor attachment to catch shallow water, and a handful of long-term owners report a unit going quietly offline or a battery draining early after a year or more. There is no temperature sensor to watch for the cold, only the leak contact itself.

Frequently Asked Questions

Which is better overall: the eufy Security Flood & Freeze Sensor E20 or the Third Reality Water Leak Sensor?

The eufy Security Flood & Freeze Sensor E20, for a Eufy HomeBase home that also wants freeze warnings and a five-year battery. The Third Reality Water Leak Sensor is the better value for a Zigbee home that wants a cheap, very loud alarm.

What is the biggest difference between the eufy Security Flood & Freeze Sensor E20 and the Third Reality Water Leak Sensor?

Freeze coverage. The eufy Security Flood & Freeze Sensor E20 watches for both water and freezing pipes, while the Third Reality Water Leak Sensor senses water only and has no temperature or freeze alerts.

Do both of these water leak sensors need a hub?

Yes. The eufy Security Flood & Freeze Sensor E20 needs a US Eufy HomeBase, and the Third Reality Water Leak Sensor needs a Zigbee hub. Neither connects directly to Wi-Fi.

Which of the two has the louder alarm?

The Third Reality Water Leak Sensor, at 120 dB on the device. The eufy Security Flood & Freeze Sensor E20 uses a 75 dB buzzer, but it also adds a red LED that the Third Reality Water Leak Sensor does not have.

Who should buy the eufy Security Flood & Freeze Sensor E20?

A Eufy HomeBase household watching a garage, basement or laundry for both leaks and freezing pipes, that wants a long battery and a probe for tight spots.

Who should buy the Third Reality Water Leak Sensor?

A Zigbee home on SmartThings, Home Assistant or Hubitat that wants an inexpensive, very loud leak alarm and can add a Smart Bridge MZ1 for Google Home or Apple HomeKit.

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