Does the Flo by Moen Smart Water Monitor and Shutoff live up to its smart water moniker? That’s what we recently set out to do by installing the latest version of the Flo by Moen shutoff system in our Digitized House Review smart home. The device not only monitors and categorizes water usage throughout the home to help promote water conservation, but more importantly offers realtime leak detection and automatic main waterline shutoff in the event of a major leak event. Read on to get our in-depth review.
Review Summary
Purchase
Buy Now: From Moen ($475-760)
Buy Now: From Amazon (399-$560)
The Smart Water Monitoring and Automated Shutoff Landscape
Flo by Moen has been in the market for a few years, and competes with similar whole-home water monitoring and automated shutoff products offered by Phyn, Kohler, and others. The Phyn Plus Smart Water Assistant + Shutoff (2nd gen) and Kohler H2Wise+ probably most closely align with Flo by Moen with respect to features, capabilities, usage model, and price range. The Phyn and Kohler offerings, by the way, are essentially the same product (see our detailed review on the Kohler H2Wise+), though the Kohler-branded version brings some additional intelligence when used with Kohler-branded plumbing fixtures.
What can you expect with this genre of smart water devices? First, since they install on the main water line coming into the home, you can expect to get water usage and history by fixture type for devices connected upstream of the monitor, as well as water pressure monitoring. Secondly, you can expect automated daily health checks of your plumbing system (or water network, as we like to refer to it) to detect for failing components or microleaks. Thirdly, due to the built-in shutoff mechanism, they can automatically turn off the water main in the event of a catastrophic leak to prevent or minimize water damage to the structure. And lastly, you can expect anywhere, anytime app access to check on water usage, review alerts and notifications, and to remotely switch off your water main with the swipe of a finger.
On the subject of fixture type, the central smart sensors in these monitors are designed to use algorithms and AI to discover plumbing fixtures and then place them into meaningful device groups or categories for reporting. So, while they try their best to correctly identify these devices, don’t expect them to be entirely perfect in this regard.
Read on to discover how the Flo by Moen product does on these expectations.
Flo by Moen Review: Out of the Box
Moen offers the Flo system in 3 different mainline sizes, including 3/4 in., 1 in., and 1.25-in, differentiating itself from the Phyn and Kohler products that are only available in a 1-in. size. Generally, you will want to select a size that is the same or larger than your mainline so as to not impede water flow or cause reduced pressure. Suggested retail cost for Flo range from $499 to $799 depending on the mainline size, but you can expect some level of discount directly from Moen, Amazon, and other online retailers.
In the case of Flo, the overall dimensions of the valve housing and clearances required around it increase proportionally with mainline size, so also keep that in mind when selecting one for your home. We reviewed the largest-available 1.25-in. version, but if you are tight on space consider using the 3/4 in. or 1 in. versions.
The Flo Shutoff valve housing itself is molded in navy blue, and hides the electronics, Wi-Fi radio, and the waterway with a motorized ball valve that’s employed to control water flow. A green thumb turn on the front of the valve indicates the position of the ball valve: when the thumb turn is parallel to the water flow the valve is open; when perpendicular to the water flow it’s closed. The ball valve itself is chrome plated to promote long life.
The waterway features a plastic turbine on its outboard port, which is used to accurately measure water flow and usage.
Also included in the box are an temporary plastic spacer for use during installation, a power adapter with 10-foot cable, power adapter wall bracket, and wall anchors for the bracket. Do keep in mind the Flo valve itself does not utilize a bracket, so its weight must be fully supported by the surrounding plumbing system. A postcard containing a QR code encoded with the unit serial number and MAC address are also included, and are used when initially pairing the device with the required Moen Smart Water Network phone app.
Overall, the Flo setup is well thought out and appears to be ruggedly built. The 1.25-in valve is quite heavy, largely due to its physical size, motorized 1.25-in. ball valve shutoff mechanism, and solid brass fittings and tailpieces.
Flo by Moen Review: Installation and Setup
Physical installation of the Flo Shutoff is best handled by a licensed plumber, since it requires turning off the water supply and cutting into the mainline plumbing itself, and furthermore may require more twists and turns of plumbing to accommodate it. However, in general the process is straightforward in the event you want to undertake this as a DIY project and have the requisite plumbing tools and skills.
Moen does offer rough-in kits to plumbers and DIYers in various sizes and configurations that can be purchased in advance of the Flo by Moen Shutoff itself. These kits include an inline spacer and various fittings that precisely match the end-to-end dimensions of the Flo valve, and would be useful during new construction or remodels where future installation of the valve is desired. The rough-in kits are designed to enable everyday water flow and can be left in place indefinitely. Once the rough-in pieces have been installed and tested, a future installation of the Flo valve is a relatively simple process.
In the case of our retrofit installation, we had a 1-in. mainline so purchased a pair of stainless steel 1.25 x 1.0 bushings to adapt the 1.25-in. brass tailpieces at both ends of the Flo valve to a 1-in. NPT threaded pipe size. And since our system is 100% plumbed with flexible PEX plastic water lines and fittings, we also purchased SharkBite adapter fittings to make the final transitions from threaded NPT pipe to PEX pipe. In this fashion there was no need to solder any joints.
The Flo valve can be installed either horizontally or vertically. In our case, due to the existing location of the main water shutoff valve and its proximity to a water softener system, we elected to create a new S-shaped plumbing route so the Flo valve could be installed vertically. After we turned off the main water valve, we severed the incoming water line, then used brass SharkBite quick-connect fittings and short lengths of PEX pipe to fashion the new plumbing route. Additionally, we used C-shaped conduit clamps at the top and bottom of the new plumbing section to support the added weight of the pipe, fittings, and the Flo valve.
To wrap up the plumbing phase, we installed the supplied Flo spacer as a placeholder for the Flo valve, then turned the mainline back on to test the system for leaks. After taking care of a few minor drips in the brass portions of the system by using teflon tape, we turned off the water again and replaced the spacer with the Flo valve. Finally, we mounted the power adapter above the valve and connected its cable to the top of the valve, then followed the guided instructions in the Moen app to connect the valve to WiFi and complete the installation. After a few moments, the green LEDs on the top of the valve came alive and the Flo was visible on the app home screen.
Among the initial setup tasks is configuring the Home Traits panel. Here, specifics around home size, number of occupants, and water consumption goals are set. One click down, the Appliances & Amenities panel enables checking off the type of indoor and outdoor fixtures, appliances, and other amenities present in the home. The Flo system will then take this information into account as it attempts to properly categorize usage.
Video: Watch Flo by Moen in Action
Flo by Moen Review: How it Works
Startup and Learning Mode
Once Flo by Moen is up and running, it immediately begins measuring whole home water usage through its internal sensors and drops into Learning Mode—a week or so of AI-enhanced learning on the fly. During this initial training period, the automated shutoff feature is disabled and the My Flo Modes—including Home, Sleep, and Away states—are disabled as well. At this stage, the system is making educated decisions on specifically what type of device or devices are consuming water at any point in time. It does this by sensing and dissecting the water flow, water pressure, and event duration footprint and matching that against its knowledge base of devices.
The goal of course is to measure and categorize water usage as closely as possible, while learning about the typical water usage events occurring day to day. In doing so, the system intends to differentiate between normal water usage events and potential unusual events (e.g. those that may indicate a leak or high flow event). In those unusual cases, the automatic mainline water shutoff feature may be activated instantly to prevent catastrophic water damage, or a notification may be raised in the app so the homeowner can make a decision on how to handle it.
Realtime Monitoring and Instant Shutoff
From the moment it’s turned on, the Flo by Moen sensors begin tracking realtime water use in gallons per minute (GPM) and water pressure (PSI), as well as logging each and every water event. An event may be something as simple as a toilet flush or momentary opening and closing of a faucet, or longer and more complex events such as baths, showers, landscape irrigation, or water softener regeneration. In each event case, the system logs the device type/category, date and time, duration in minutes and seconds, and water volume.
In the Moen app home screen, a Whole Home Controls section appears when the Flo is added, and most importantly, the Flo Shutoff switch is front and center so you can remotely and instantly turn the water main on or off from here. We say instantly since that is precisely how it happens: within a few seconds of tapping the button, Flo will spin up its motor, and with a servo-like whir the ball valve rotates 90 degrees to shut off the water main.
The My Flo Modes are also selectable from the Whole Home Controls section.
The Joy of Stats
If you’ve never experienced whole-home water monitoring, you may be in for some surprises and shocks. Surprise! Who knew someone in the home was taking 45-minute showers and using 60+ gallons of water each time? With Flo by Moen, you’ll be able to see those leisurely shower events in the Moen app, along with the start time, duration, and gallons used—in case you want to do some sleuthing to determine the guilty party. Shock! Did you really know how much water your household was using every day? Probably not. Your new water data source is a far cry from the mundanity of a monthly water bill.
Moen offers plenty of options on how to inspect water usage. For a snapshot of realtime usage, just tap the Flo Shutoff tile from the app home screen, and from the Overview panel you can get current water pressure, flow rate, and area temperature readings through speedometer-type meters. Below the meters, you can get Sensor Trends, line charts for flow rate, pressure, and temperature plotted for the last 7 days, last 24 hours, or realtime.
On the Usage tab, cumulative water usage for the day or week are visible in a meter and accompanying bar chart, while rolled-up Usage By Fixture (or category) over the selected period appears below that.
Flo by Moen Usage panel, showing week-to-date total actual water usage versus goal (set by user in the app). 
Flo by Moen History panel, showing last 7 day usage by fixture category. 
Flo by Moen app History, showing shower events over previous week. 
Flo by Moen app History screen, depicting events by category. Individual events can be edited to reflect the proper fixture/device generating the usage.
But the most telling information lies in the History panel. Here, fixtures and categories are more finely segregated, and individual categories can be expanded to reveal all individual events and their details. Again, the metrics at this event level include date, time, duration, and water volume.
How accurate was Flo at properly identifying and categorizing the plumbing devices on our water network? In general, it did an admirable job at placing devices into broad categories, such as Faucet, Shower, and Toilet. For devices it could not specifically identify, it tended to place them into a general Appliances category—this catch-all classification included things such as dishwashers, in-door water dispensers, craft ice makers, washing machines, pot fillers, water softeners, and other devices.
Furthermore, while it’s not evident from the user interface, each individual water event can be tapped to enable editing of its fixture or category. For instance, if you know a specific Shower event was indeed a Garden Hose event, you can tap the Wrong Fixture button and select the correct one. Flo ideally would then be able to properly categorize similar events in the future. Following editing, the specific event will appear under its new category, with subtext indicating the previous category. This data was also reflected in the reporting tools.
In practice, however, we found that after editing an event to reflect a new device type, Flo was generally not able to correctly identify the device the next time it was used.
My Flo Modes
The My Flo Modes are selectable from the Moen app home screen, and are primarily designed to adjust how and when the automatic shutoff feature works. These modes work as follows:
- Home Mode: The normal mode for day-to-day use. Home Mode brings the regular level of leak and usage protection, including alarm notifications for higher-than-normal usage and automatic water shutoff enablement. You’ll typically get an alert or notification before Flo takes any drastic action around shutting off the water.
- Away Mode: The mode to use when you are away for an extended period of time or on vacation. Away Mode brings an additional level of leak and usage protection by learning what usage is like when you’re away. In this mode, Flo can instantly trigger an automatic shutoff when it detects higher than normal usage or when it thinks a major leak has occurred.
- Sleep Mode: This mode is not what you think. Sleep Mode simply ignores all proactive and real-time tests and silences all alarm notifications, and is designed for use when irregular water usage is expected like filling a swimming pool or spa, or having several guests stay over. So when you are sleeping, be sure to use Home mode.
Alerts, Notifications, and Health Checks
Flo can generate myriad alerts and notifications via text message, email, phone call, or in-app when in Home or Away mode based on extremely granular settings in the Flo Notifications panel. The choices are extensive in both modes, and are categorized into Critical Alerts, Warning Alerts, and Information Alerts. In all, there are 27 individual settings for Home mode and another 27 settings for Away mode. Beneath each of those, you can individually opt in or out of text, email, call or in-app notifications. Suffice it to say, you’ll want to carefully review these to ensure you are getting what you need for your situation.
Flo also provides what they call FloSense, a global alert sensitivity setting. A slider with a range from Less Alerts to More Alerts dictates how the system will respond with alert notifications when unusual activity is detected. So if you find you are still getting too many alerts, just crank down this setting.
Flo has also built-in a plumbing health check feature, referred to as MicroLeak Test. By default, this general plumbing health check runs once per day by automatically turning off the water main and monitoring for any leaks or abnormalities in the pressurized system. After it runs its course over a span of 2 to 4 minutes, the water main is turned back on and results get reported based on its settings in the Notifications panel.
To test this feature, we opened a faucet to produce a flow of about 1/10 gallon per minute then initiated a manual MicroLeak Test. The test immediately detected the water flow and raised an alert in the app, noting a 10.79% drop in water pressure. The app suggested we check all the fixtures in the house to make sure they were tightly closed and sealed.
Flo by Moen notification, following unexpected water usage during Away Mode. 
Flo by Moen app home screen, with alert reporting an automatic shutoff while in Away Mode. 
Flo by Moen app home screen, with critical alert notification and automatic shutoff reporting while in Away Mode. 
Flo by Moen app Alerts screen, with logging of recent alert notifications. 
Flo by Moen app following a scheduled Microleak Test, where a minor leak was detected.
Leak Detection and Automatic Shutoff
Moen says leaks as small as one drip per minute can be detected. We were not able to verify that, but we were able to simulate a larger “leak” in our water network.
In our testing, we simulated an Away Mode leak and automatic shutoff scenario. First, we set FloSense to maximum sensitivity. Secondly, we adjusted Away Mode Notifications to trigger instantly and immediately notify when any unexpected water use was detected, and lastly, we put the Flo into Away mode.
Then, all that was left was to turn on some water, so we opened a bathroom sink faucet. Instantly, we received a text indicating unexpected water usage, and immediately we could hear the whir of the Flo as it activated its shutoff valve and turned off the water. This all happened within a handful of seconds.
Manual Shutoff
In the event of a power outage or network outage, the Flo shutoff valve can still be operated manually by using the included hex wrench. The thumb turn must be fully depressed prior to rotating it clockwise the required 90 degrees to open or close the valve.
Flo by Moen Review: Integrations
Flo by Moen can integrate with several smart home ecosystems, including Amazon Alexa, Google Home, Nice, Ring, and Alarm.com. But don’t expect too many features to be exposed through these integrations.
By way of example, we tested the Google Home integration—but functionality was limited to controlling the open/close position of the shutoff valve, as well as the mode selector. However, this minimal level of integration is typical for Google Home and may not fully represent other platforms.
Flo by Moen Review: What’s Missing and a Few Issues
Flo by Moen is generally very well thought out and operates without a hitch. However, while the reporting through the recommended Moen Smart Water Network app is extensive, you can only review data from the past week. For example, there is no facility to view the history of previous months, or to compare August of this year to August of last year.
In fairness to Moen, if you want more in-depth reporting by week, month, or year, you can elect to use the standalone Flo by Moen app instead. Flo also offers a web interface, with extensive controls and similar deep reporting.
On issues, few were encountered and they were generally minor. Over the month or so that we conducted our testing, we occasionally experienced sluggishness when launching the Moen Smart Water Network app. In these cases, the home screen failed to draw, likely attributable to network issues. A relaunch of the app a few moments later typically resolved those issues. Also, when cycle testing the Flo shutoff valve by repeatedly tapping the open/close button in the app, the app stopped responding. We relaunched the app and rebooted the valve after those incidents and all seemed to be fine.
The Bottom Line: A Water Network Safety Net
The Flo by Moen Smart Water Monitor and Shutoff is an ideal water network safety net for homeowners desiring to monitor whole-home water usage, practice water conservation, and protect their homes from catastrophic water damage. We were impressed by its overall smooth operation through several weeks of testing on our water network, solid build quality, respectable accuracy in monitoring and measuring usage, and overall ease of use. We highly recommend it.
