Honeywell RWD21 Review

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    Water damage is one of the biggest threats to your home – it can cause thousands of dollars in damage in a few hours and as a homeowner you need to be on constant alert for leaks! Fortunately a leak detection alarm like the Honeywell RWD21 can alert you to leaks the moment water is detected.

    In this guide we will review the Honeywell RWD21 water leak alarm to make sure it is a good choice for protecting your basement, crawl space, attic or other hard to monitor area of your home to help prevent water damage before it sets into the walls and floor.

    Honeywell Water Sensor
    • Detects as little as 1/16″ of water
    • Emits loud alarm at the first sign of water
    • Easy to set up and install multiple sensors across the home
    • Powered by 9V battery

    The alarm is a good choice if you are looking for an affordable alarm with basic functionality.


    • Low battery alarm
    • Small profile is easy to install
    • Good water detection


    • No WiFI or phone alerts

    We don’t recommend this alarm if you are a landlord or property owner looking for a remote monitoring system since this alarm only emits an audible alarm!

    Power Source9 volt battery
    Alarm TypeAudible alarm
    Life SpanAt least 5 years
    Alarm Sensitivity1/16″ of water
    PriceAbout $10

    How To Install

    The RWD21 is easy to install. All you have to do is install a 9V battery into the unit, then place the sensor in the target location. The 9V should last for at least 2 years and the unit will begin to emit a low battery alarm when the power gets low.

    What’s Included

    Inside of Honeywell Water Alarm

    The RWD21 comes with one water sensor. It does not include a 9V battery that is needed for power so you will have to order that separately.

    After receiving the alarm all you have to do is install the battery and place the sensor in an area you need to monitor for flooding and leaks.

    Troubleshooting, Potential Problems and Warranty

    The Honeywell RWD21 is well made – so it is unlikely to malfunction. The most common problem is the batteries running out and when that happens all you have to do is put in a new 9v battery.

    Where to Buy The Honeywell RWD21 Water Sensor

    The Honeywell RWD21 is one of the most popular home sensors and available at a number of stores. The best place to buy the RWD21 is at Amazon – they have good pricing and it can be delivered in a few days – plus you can order as many as you need!

    Another good place to buy these sensors locally is at Home Depot, Lowes or your local hardware store.

    Editors’ Recommendations

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