Live nowPrime Day 2026October 6 to 7, 2026Starts in06d06h19m20sSee the deals
Meross Smart Multi-Function Water Leak Sensor

Meross Smart Multi-Function Water Leak Sensor

Leak, drip, freeze and water-level detection in one battery-powered sensor, with a loud 100 dB alarm but no Wi-Fi or Matter of its own.

Launch Year: 2026

Model: MS420H

See the 10 best selling water leak sensors
Open selection
Price alerts

Water Leak Sensor price drops, every week

We check the price of every Water Leak Sensor in the catalog daily, and email you the drops.

Smart home deals and news, straight to your inbox

Price drops, new releases and the smart home news worth knowing.

No spam. Unsubscribe in one click.

Your subscription could not be saved. Please try again.
Please enter a valid email address.
Your subscription has been successful.
Our review

Meross MS420H Review: A Four-Way Water Sensor That Needs the Meross Matter Hub

The verdict

The Meross Smart Multi-Function Water Leak Sensor (MS420H) is a rugged IP66 leak detector that goes beyond simple wet-floor sensing, adding drip, freeze and water-level detection plus a 100 dB local buzzer and a bundled 1.5 m probe. It is at its best for buyers already using, or willing to add, the Meross MSH450P hub, because the sensor talks Bluetooth Low Energy and only gains app alerts, Matter and automation through that hub. Buyers who want a standalone Wi-Fi leak sensor should look elsewhere.

Best for
  • Homes with the Meross MSH450P hub
  • Basements and laundry rooms that can freeze
  • Tanks and bathtubs needing water-level alerts
  • Long-battery, low-maintenance installs

Pros

  • Four detection modes: leak, drip/rain, freeze and water level
  • Loud 100 dB alarm with adjustable volume and mute
  • IP66 weather resistance and a -20 to 60 C operating range
  • Up to four years on a single CR123A battery
  • Includes a 1.5 m extension probe for tight spots
  • Matter support for Apple Home, Google Home, SmartThings and Home Assistant through the MSH450P hub
  • Up to three conditions can be combined to reduce false alarms

Cons

  • Needs the separately sold Meross MSH450P hub for app alerts, Matter and automations
  • No Wi-Fi radio of its own
  • No Alexa support for the Matter water leak device type
  • No ambient temperature readout
  • No tamper alert
  • Weight is not published by the manufacturer

Who is the Meross MS420H for?

This sensor suits households that already run Meross's newer hub, the MSH450P, or that are building a small multi-sensor setup around it. It is also a good fit for hard-to-reach spots where running power is awkward, since it runs for years on one CR123A battery. Its four detection modes (leak, rain or drip, freezing conditions and water level) make it useful in a basement, a laundry room, an unheated garage or beside a water tank, and the included 1.5 m probe lets the sensor body stay accessible while the tip sits where water would collect.

What stands out on paper

The headline feature is the 100 dB built-in buzzer, loud enough to be heard from another room and adjustable or muted when needed. It carries an IP66 rating and works from -20 to 60 C, so it tolerates damp and cold locations better than an indoor-only sensor. Up to three detection conditions can be combined before an alert fires, which cuts down on false alarms from a splash or a humid morning, and the top electrodes and probe height are adjustable. The single CR123A battery is rated for up to four years, among the longest in this category.

What to know before you buy

The MS420H is not a standalone smart device. It has no Wi-Fi radio: it connects to the Meross MSH450P hub over Bluetooth Low Energy, and remote push notifications, Matter integration and automations all depend on that hub, which is sold separately. The standalone kit variant includes the hub, while the sensor-only unit does not. Alexa is not a route here either, because Alexa has no water leak sensor type in its Matter device support. There is also no ambient temperature reading and no tamper alert, this is a water and freeze detector rather than a general environmental sensor.

Is the Meross MS420H worth it?

At a budget sensor price, and with a battery that lasts years, the MS420H packs a genuinely useful set of detection modes plus a loud local alarm. The value depends on owning the Meross hub: with it, the sensor adds remote alerts, Matter support across the major platforms and automation triggers to other devices. Without it, the sensor is a loud local alarm and little more, so buyers outside the Meross ecosystem should factor in the hub or choose a Wi-Fi leak sensor instead.

Frequently asked questions

Does the Meross MS420H need a hub?

Yes, for anything beyond the local alarm. The sensor communicates over Bluetooth Low Energy and needs the Meross MSH450P hub for phone alerts, Matter integration and automations. The sensor-only unit does not include the hub.

Does the Meross MS420H work with Alexa or Google Home?

Google Home works through the MSH450P hub over Matter. Alexa does not, because Alexa has no water leak sensor capability in its Matter device support.

How long does the battery last?

Meross rates the single CR123A battery at up to four years of life, which suits hard-to-reach placements.

What can it detect?

It detects water leaks, rain or drips on its top electrodes, freezing conditions and a set water level through the included 1.5 m extension probe. Up to three conditions can be combined before it alerts.

Is it suitable for outdoors?

It is IP66 rated and works from -20 to 60 C, so it handles sheltered outdoor and unheated locations such as a garage or a basement, though it is not intended for full immersion.

Does it work with Apple Home?

Yes, through the Meross MSH450P hub, which republishes the sensor over Matter so it can be added to Apple Home.

At a glance

Summary

Everything this water leak sensor supports, grouped by category.

Size & Materials
Weather Resistance (IP66)1.2 × 1.2 × 3.3 in (31.5 × 29.5 × 85 mm)
Included accessories
Sensor Cable
Connectivity
Bluetooth
Integrations
Google Home (MSH450P Hub required)Apple HomeKit (MSH450P Hub required)Samsung SmartThings (MSH450P Hub required)Home Assistant (MSH450P Hub required)Matter (MSH450P Hub required)
Sensors
Water LeakTemperature (Freezing conditions)
Alerts
Water Leak AlertsFreeze Temperature Alerts
Features
On Device Alert Sound

Price History

Loading price history...

Price alerts

Waiting for a better price?

We check this price every day and email you when it drops, along with the rest of the week's deals.

Company
Meross logo

Meross

4.3/ 5 avg ratingChina flagHeadquartered in China

Meross is a smart home brand offering affordable connected devices such as smart plugs, switches, garage door openers, LED lighting and sensors. Many Meross products support Apple HomeKit alongside Alexa and Google Home, making them a budget-friendly option for HomeKit users. The brand is popular for adding smart control to everyday home fixtures.

Full specifications

Every spec, organized

Browse the full breakdown by category. Tap the on any row for what it means, or the for sources and documentation.

Size & Materials
Weather Resistance

IP66

Dimensions

1.2 × 1.2 × 3.3 in (31.5 × 29.5 × 85 mm)

Weight

?

Included accessories
Sensor Cable

YES

Ships with a 1.5 m extension probe that reaches behind washing machines, under sinks or into tanks.

Power
Wired

NO

Battery Type

CR123A

Battery Life

4 years

Connectivity
2.4 GHz WiFi

NO

5 GHz WiFi

NO

Bluetooth

YES

Bluetooth Low Energy link to the Meross MSH450P hub; the sensor has no Wi-Fi radio of its own.

Z-Wave

NO

Zigbee

NO

Thread Protocol

NO

Other

NO

Integrations
Google Home

MSH450P Hub required

Matter, and therefore Google Home, arrives through the Meross MSH450P hub that bridges the sensor.

Alexa

NO

Alexa has no water leak sensor type: the Matter Water Leak Detector has no Alexa capability mapping, and bridges such as SmartThings or Home Assistant cannot expose a moisture sensor either

Apple HomeKit

MSH450P Hub required

The MSH450P hub republishes the sensor over Matter, which is how it joins Apple Home.

Samsung SmartThings

MSH450P Hub required

Via Matter through the MSH450P hub.

Home Assistant

MSH450P Hub required

Via Matter through the MSH450P hub; Home Assistant is a certified Matter controller and also reads Meross devices through the community meross_lan integration.

Matter

MSH450P Hub required

The sensor itself speaks Bluetooth Low Energy; the MSH450P hub carries it into Matter.

Sensors
Water Leak

YES

Temperature

Freezing conditions

Detects freezing conditions to warn before pipes burst, rather than reporting ambient temperature readings.

Tilt

NO

Alerts
Water Leak Alerts

YES

Temperature Alerts

NO

Freeze Temperature Alerts

YES

Raises a freeze alert, and up to three conditions (leak, rain/drip, freeze or water level) can be combined before an alert fires.

Low Battery Alerts

?

Tamper Alerts

NO

Features
On Device Alert Sound

YES

Built-in buzzer rated up to 100 dB, with adjustable volume and a mute mode.

On Device Alert Light

NO

Automations

YES

Through the MSH450P hub a leak, drip, freeze or water-level event can trigger other devices, for example switching off a smart plug feeding the washing machine or closing a smart valve.

On sale now

13 other Water Leak Sensors on sale

View all
Full comparison table

Compare the Meross Smart Multi-Function Water Leak Sensor with the other 33 Water Leak Sensors

All Water Leak Sensors in the catalog in one table: filter by what you need, sort by price or rating, and see exactly where this one lands.

  • 33 other Water Leak Sensors
  • 36 specs compared
  • 33 filters
Open the full comparison
Head to head

Meross Smart Multi-Function Water Leak Sensor vs the competition

View all
Meross

More from Meross

View all