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Jun 23, 2023

The 3 Best Smart Water

We've made the D-Link DCH-S1621KT our new top pick, added four other models to

We've made the D-Link DCH-S1621KT our new top pick, added four other models to the Competition section, and added testing notes after our long-term use of the runner-up pick.

Cool water can be refreshing—except when it's in the form of a puddle that seeps from a toilet. A smart water-leak sensor can lessen the impact of plumbing problems by alerting you the moment they’re detected, whether you’re at home or away. We have yet to find a smart water-leak sensor that is perfect in every way, but the D-Link DCH-S1621KT Whole Home Smart Wi-Fi Water Leak Sensor Kit includes the features and capabilities that are most important. It responds to potential danger quickly, it has a loud onboard siren, and it integrates with other smart devices.

These devices activate only if water touches them. Be sure to place them in areas where leaking water would pool.

Opt for a device with an alarm sound that is at least 80 decibels loud, as a fail-safe against missing a leak alert sent to your smartphone.

Ensure that the sensors have a stable connection to your Wi-Fi—otherwise, they won't be able to send alerts. Some devices may rely on a hub.

You can link leak sensors with other devices for extra features such as voice alerts from a speaker or the ability to trigger a light bulb.

This D-Link kit has a plug-in Wi-Fi hub with an optional sensor cable and can connect with up to 16 battery-powered remote sensors. It responds quickly to potential problems with both a loud (94 dB) siren and fast smartphone alerts.

Compatible with: Google Assistant, IFTTT

The D-Link DCH-S1621KT Whole Home Smart Wi-Fi Water Leak Sensor Kit combines the best capabilities we’ve seen available in leak sensors into one bundle. It includes a plug-in hub (and so can be placed only in areas near an electrical outlet), but it also has a removable 19-inch water-sensing cable and a 38-inch extension cord to lengthen that cable's reach. In addition, the kit comes with a matchbox-sized remote battery-operated sensor that connects wirelessly to the hub from up to 300 feet away. The hub can connect with up to 16 add-on sensors, responds quickly when it senses water or if it loses power, and features a loud (94 dB, by our measurements) siren. The system supports Google Assistant for announcing activity on smart speakers, as well as the web service and app IFTTT (If This Then That) for triggering other smart devices (such as a smart bulb) when it finds a leak. Like every other leak sensor, it has a few quirks, but it's still the best choice for monitoring more than one spot in a home.

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The Flo monitors for water and temperature changes, even in hard-to-reach places, thanks to the included extender cable. It also responds quickly to emergencies, sending smartphone notifications, emails, and texts.

*At the time of publishing, the price was $50.

Compatible with: n/a

The Flo by Moen Smart Leak Detector responded consistently both to leaks and to connectivity or power issues, and it did so faster than most of the devices we tested. It's battery powered, so you can easily place it without having to worry about access to an electrical outlet. The Flo's main unit is droplet-shaped and has sensing probes on the bottom; you can attach a 4-foot extender probe and sneak that into tight spaces, as well. We like that the Flo also measures temperature and humidity and has an onboard audible alarm (although it isn't very loud). Unfortunately, this model doesn't integrate with popular smart-home platforms like Amazon Alexa, Apple HomeKit, and Google Assistant, but it does work with Flo's water-shutoff system—a smart water valve that can turn off your home's water service if it detects a potentially catastrophic leak.

The Proteus Aquo is more customizable than any other water-leak sensor we tested. However, it has no dedicated app, it needs to be plugged in, and it's more expensive than our other picks.

Compatible with: Amazon Alexa, Google Assistant, IFTTT

The Proteus Aquo Wi-Fi Water Sensor is more customizable than any other standalone leak-detecting device we reviewed. You can program alarm times, schedule power notifications, and integrate it with Amazon Alexa, Google Assistant, and IFTTT. This device also has a loud audible alarm (85 dB), and its system can integrate up to five sensors simultaneously (including one for a sump pump). But that customization can be complicated, and Proteus offers no dedicated smartphone app (you use a web browser to handle administration tasks). In addition, the device needs to be plugged into the wall, and it's more expensive than our other picks.

This D-Link kit has a plug-in Wi-Fi hub with an optional sensor cable and can connect with up to 16 battery-powered remote sensors. It responds quickly to potential problems with both a loud (94 dB) siren and fast smartphone alerts.

The Flo monitors for water and temperature changes, even in hard-to-reach places, thanks to the included extender cable. It also responds quickly to emergencies, sending smartphone notifications, emails, and texts.

*At the time of publishing, the price was $50.

The Proteus Aquo is more customizable than any other water-leak sensor we tested. However, it has no dedicated app, it needs to be plugged in, and it's more expensive than our other picks.

I first started testing smart-home devices more than 20 years ago, back when the only smart-home devices were X10. Since 2016, I’ve covered smart-home gear for Wirecutter, and I’ve had my hands on everything from in-wall light switches, smart bulbs, and smart plugs to indoor security cameras, smart doorbell cameras, and security systems. I’ve also written tech articles for The New York Times, Wired, and Men's Health, among others.

According to the Insurance Information Institute, water damage was the second most common cause of claims from 2015 to 2019, and the second most expensive. Unwanted water can come from any number of sources, including old roofs, leaky water heaters, malfunctioning sump pumps, old toilet valves, decrepit fish tanks, and cranky washing machines. The damage it wreaks can be equally varied—water can warp floors, stain furniture, ruin old photos, and breed mold. And the aftermath of a leak can be expensive: As Home Advisor indicates, cleanup costs can be anywhere from $3.75 to $7 per square foot, depending on the type and volume of damage, as well as your location.

Smart water-leak sensors are for anyone who is worried about small leaks turning into big ones, as well as anyone who doesn't want to wait until they step into a flooded room to find out. Plenty of non-smart water-leak sensors trigger a siren when they detect water, but they may go unheard if you’ve situated them in a bathroom or deep in the basement, or if you’re not home. A "smart" water-leak sensor, however, sends alerts right to your smartphone no matter where you are. Most water-leak sensors are tiny pucks or sensor points that you can place near or underneath a water source. When a leak happens and water makes contact with the sensors in one of these devices, the detector sends you a smartphone alert, an email, and/or a text message (and in some cases it sounds an audible alarm).

Water-leak sensors are not foolproof. You do need to place them thoughtfully, so that they are in the path of where water might flow. Otherwise, water may completely bypass a smart leak sensor. Some models come with cords that allow you to better reach leaky places, while others let you combine multiple devices that communicate with a hub. Ideally, you should place multiple sensors throughout your home to cover a variety of spots where water leaks might happen.

Detectors are only an alarm system—on their own they don't protect your home from damage. You can find devices that can automatically turn off your water line when they detect a leak, but those systems typically cost hundreds of dollars and may require a visit from a professional installer or plumber, adding even more to their cost; the devices in this guide let you monitor for leaks and then take action yourself.

After continuously updating our research and our testing scores for leak devices over several years, we’ve come to the unsatisfying conclusion that there is no perfect smart water-leak sensor. However, there are several good or good-enough models that suit the needs of most people. In deciding which models to test, we consider the following features:

You can get a leak sensor that sets off an eardrum-piercing tone for as little as $10, but if you want smartphone alerts and the ability to check in on your sensors remotely via an app, be prepared to pay a bit more. The cost of smart water-leak sensors is all over the place, ranging between $20 and $100, and dependent on features, accessories, and manufacturer. Though some people may question the value of such devices, the cost to replace furniture, rugs, and memories is much higher, so we’ve concluded they’re a worthwhile investment for most people.

We set up each device according to its instructions, downloaded the necessary apps, and connected them to a Wi-Fi network or a smart-home hub when needed. For each of our tests, we used apps on an iPhone SE, an iPad, and a Samsung Galaxy J7 running Android Oreo, when possible.

Not every water leak results in a flooded basement, so we doused each smart water-leak sensor with four different amounts of water to see whether it would react—and how quickly. Specifically, we measured sensitivity using a spray bottle, a dropper with ¼ teaspoon of water, a full teaspoon, and a ⅛ cup measuring cup. We completed those tests about 25 feet from our router; we also tested each device from the farthest point inside our test house, about 40 feet away. With the exception of a few models, most smart water-leak sensors cannot be completely submerged—although it's possible for some to dry out and be fine, we did have one model that completely died on us. (Most manufacturers put a warning on the packaging or in the manual regarding this point.)

We also timed how fast each sensor was in alerting us, both through an audible alarm (when available) and via push notification, text, or email. When possible, we integrated water-leak sensors with Amazon Alexa, Apple HomeKit, and Google Assistant, and we set up triggers using IFTTT, which allows you to add an extra alert option. For instance, we set up a trigger that would turn on a smart light bulb in the living room whenever the device detected water.

Wirecutter takes security and privacy issues seriously and investigates as much as possible how the companies whose products we recommend deal with customer data. As part of our vetting process for smart water-leak detectors, we looked at all of the security and data-privacy practices behind our picks. We also reached out to all of the companies that produced our top picks and had them answer an extensive questionnaire (see Privacy and security: How our picks compare) to confirm information we think should be of primary concern for any potential buyer.

Smart water-leak sensors are pretty low risk when it comes to concerns about being hacked, but we always prefer to use the highest form of security available. All of our picks require a password for the app or web interface, but only Proteus offers two-factor authentication, a common system that does a good job of ascertaining that you are indeed you by sending a verification code to your phone if you attempt to log in to the app. (And it's not required.) Our other two picks currently don't offer 2FA, a situation that we hope will change.

Data sharing is a bigger concern, but it's often what makes these devices work better. None of the companies behind our picks say they will share information. However, if you opt to connect your sensor to a third-party smart platform like Amazon Alexa, Google Assistant, Samsung SmartThings, or IFTTT, you are then also subject to that entity's data security and privacy practices. (Notably, Apple says that no personal data is ever shared with third parties when devices are connected via HomeKit.)

Wirecutter long-term tests all of its picks, and that includes keeping track of hardware and software incidents. Should we find any privacy or security concerns affecting any of our selected models, we’ll report them here and, if necessary, update or alter our recommendations.

This D-Link kit has a plug-in Wi-Fi hub with an optional sensor cable and can connect with up to 16 battery-powered remote sensors. It responds quickly to potential problems with both a loud (94 dB) siren and fast smartphone alerts.

Compatible with: Google Assistant, IFTTT

The D-Link DCH-S1621KT Whole Home Smart Wi-Fi Water Leak Sensor Kit is the best all-around leak detector we tested. It reliably delivers fast alerts when water is present, both with an audible alarm and push notifications to your smartphone. The kit includes a plug-in hub with an epically loud siren (94 dB) and also comes with an optional water-sensing cable so you can monitor a range around the outlet. The kit can scale for small or large homes, too, since the hub can support up to 16 add-on battery-powered remote sensors (one is included) for keeping tabs on water heaters, sinks, washing machines, toilets, and other vulnerable areas. Admittedly, the D-Link DCH-S1621KT has a few shortcomings, but it's still the best smart leak detector currently out there.

The DCH-S1621KT system provides two methods for detecting water: a Sensor Pod (a little battery-powered puck with metal probes on the bottom), which you place in a spot where leaking water may pool, and a 19-inch water-sensing cable, which you can spread out to cover a larger, less specific area (you can add a 38-inch extension cord between the hub and the sensing cable for harder-to-reach places).

In our testing, we found that both the pod and the cable detected water reliably; we also like that you can opt to use one or both at the same time. The hub's siren registered at 94 dB on our meter, about the same volume as a lawn mower—it's one of the loudest leak alarms we’ve tested. Smartphone notifications typically came within a second of the system's detection of water, whether we used the cable or the Sensor Pod. The kit comes with one Sensor Pod, and you can purchase others individually for $25 each; we tested a pair of Sensor Pods over several locations in our test house, from up to 40 feet away from the hub, and encountered no connection issues.

We had mixed results, though, in receiving notifications that a Sensor Pod was offline. When the hub loses power, the app sends a smartphone notification; that worked reliably in our tests, taking about three and a half minutes, faster than on any other device we tested. However, when we cut power to a Sensor Pod, our results didn't come in as fast (see Flaws but not dealbreakers below).

D-Link's alarm is reassuringly loud, and you can silence it directly on the hub itself or through the app. It won't permanently mute, however, if the system continues to detect water; instead the hub sends out a quick blast every 30 seconds until you clear the water.

The D-Link app lets you easily glance at the status of all connected sensors. Tapping on each one provides a record of events in the past 24 hours, and in the case of the Sensor Pods, a peek at the battery life. The D-Link hub can link to Google Assistant speakers so that they make a voice announcement when it detects water (and also when the water is cleared). It's also compatible with IFTTT, which we used to create an automation that would trigger a Wyze Plug to turn on a table lamp and prompt a Wyze Bulb Color to turn on whenever water was detected—a handy fail-safe option for ensuring that you’re notified if you aren't within reach of your phone, if you aren't within earshot of a sensor, or if you have hearing loss.

Although you can mute the hub's siren in the app and at the device, it will start up again after 30 seconds so long as water is still present, and it will continue until the problem is cleared up. That could be a problem if you’re away from home, especially if you have pets or guests who may be bothered by the alarm. We would love to see a way to fully silence the alarm.

One of the things we loved about the D-Link hub in our tests was how quickly it alerted us when it lost power. Unfortunately, those same superpowers don't extend to the Sensor Pods. When the add-on Sensor Pods lose power, the app doesn't alert you directly, which we think is a problem. Although you can see that the sensor is disconnected in the app, you have to be looking at the app in the first place to notice. There's also a lengthy delay before the app even notifies you—approximately 48 hours, according to our testing. We realize that the Sensor Pods remain in a low-power mode to conserve battery life, but the response time should be faster, and the app ought to send a smartphone notification as soon as possible.

Finally, D-Link does not offer two-factor authentication, a mainstream security measure that lets the app confirm your identity when you attempt to use it. Although we don't think that omission is a dealbreaker for this type of device, we would expect a company like D-Link to offer this type of security, and we hope that it adds the feature soon.

The Flo monitors for water and temperature changes, even in hard-to-reach places, thanks to the included extender cable. It also responds quickly to emergencies, sending smartphone notifications, emails, and texts.

*At the time of publishing, the price was $50.

Compatible with: N/A

The Flo by Moen Smart Leak Detector is the only cordless water-leak sensor we tested that delivered quick alerts concerning water, temperature, humidity, and Wi-Fi connectivity. Powered by a replaceable button battery (CR123A), the Flo smart detector is easy to mount to a wall or to place under a washing machine, a refrigerator, or anywhere else. The main detector has sensor probes on the bottom, with more at the tip of an optional, included cable that can extend the reach up to 4 feet. It also has an audible alarm and the option to connect to the larger Flo by Moen Smart Water Monitor & Shutoff system.

The Flo device has two ways of detecting water. Three metal probes are located on the bottom of the main detector, which is shaped like a water drop. It also comes with an optional 4-foot cable with a sensor disc at the tip. Unlike with some of the other devices on our list, you can't use both sets of sensors simultaneously; the cable plugs into a wall mount, which can keep the main detector from being submerged but prevents it from detecting water.

We ran tests using the probes on the actual detector as well as those on the tip of the extender cable. On average, the device's audible alarm and tiny red LED triggered within one second, with smartphone alerts clocking in regularly at the six-second mark. We also repeatedly removed the battery and found that the app would consistently send a disconnection alert within an hour. Although the Flo device has an audible alarm, the volume is just 60 dB, according to our measurements, substantially quieter than the alarms of our other two picks (and comparable to the sound level of a normal conversation).

The Flo's audible alarm beeps for 10 seconds every 13 seconds. You can silence it in the app, which also gives you the option to block alerts for the next five minutes or 30 minutes after the initial alarm. This is a nice perk over our top pick. After all, having a basement filled with water is enough of a headache—having to walk through it to silence beeping is a whole other level of nightmare.

Although an app that monitors for water leaks is probably the one app you hope you’ll never have to use regularly on your phone, the Flo by Moen app for iOS and Android devices is notably easy to use and visually pleasing, and it has a few interesting extras. Aside from an Activity Log, the app displays humidity and room-temperature measurements, as well as averages on those stats for the previous 24 hours and seven days. It also offers a clear battery reading (versus those that tell you it's all "good"), as well as a Device Settings section where you can set custom alerts for humidity, room temperature, and battery levels. You can also configure all three of those to send push notifications, emails, or text messages, but not to trigger other smart-home devices. That missing capability is disappointing, since we find a lot of value in being able to link devices. For instance, you might configure smart speakers to play an audible announcement or smart bulbs to turn red if the system detects a leak. You can partner this Flo detector with the Flo by Moen Smart Water Monitor & Shutoff, a $500 whole-house setup that supports Amazon Alexa, Google Assistant, IFTTT, and Control4 systems.

After we completed our original testing, we gave the Flo by Moen sensor a fresh set of batteries and placed it next to a toilet. After letting it sit there for about a year, we received a message indicating that the battery was down to 20%. The few times it triggered during that period were due to splashes from cleaning or the bathtub, which assured us that the device was still working. We had one incident where a shower triggered it, too, but we discovered that we had set our humidity alerts too low.

The Proteus Aquo is more customizable than any other water-leak sensor we tested. However, it has no dedicated app, it needs to be plugged in, and it's more expensive than our other picks.

Compatible with: Amazon Alexa, Google Assistant, IFTTT

The Proteus Aquo Wi-Fi Water Sensor is unlike any other water-leak sensor we’ve ever reviewed. It delivers lightning-fast response times and customizable alert times so you can set the audible siren to go off after 20 minutes, say, or trigger a disconnection notice after 10 minutes. In addition, it provides the option to notify multiple phones and email addresses in an emergency—and it can send phone-call alerts (for a fee). Proteus also sells a splitter, so you can attach five sensor cables to simultaneously monitor multiple spots in the same immediate area. The Proteus Aquo needs to be plugged into a wall outlet, which may be an issue in some homes, and it doesn't have a dedicated app, which is inconvenient. Also, we found its support for Amazon Alexa and IFTTT to be complicated. And not least, this Proteus model is more expensive than either of our other picks.

So why do we like it? Throughout our testing, the Proteus Aquo sensor gave us some of the best response times, firing off audible alerts within two seconds and text messages within four seconds. That siren was loud, registering at 85 dB on our decibel meter. Since the device doesn't have a dedicated app (more on that below), it doesn't send smartphone notifications. But you can designate as many phone numbers (for texts) and email addresses as can fit into 400 characters.

You manage those contacts and alerts, as well as all other settings, using Proteus Sensor Cloud, a portal you access through a web browser. You can opt to disable the siren or set it for a specific amount of time, as well as designate how often you want the system to keep sending alerts and whether you want notifications once the water is gone. In our tests, the Proteus Aquo provided an excellent response to connectivity issues—that is, when it lost either power or the Wi-Fi signal—with alerts that we could customize to trigger in as little as 10 minutes after it detected a problem.

The Aquo looks a little like a miniature spy camera. The water sensor itself is on the end of a 6-foot cable, which you can leave on its own or mount to the floor or wall via the screw holes on either side of the metal contacts. Proteus also sells a splitter ($6), so you can connect up to five sensors at once, including a sensor to monitor a sump pump. Curiously, however, the system can't distinguish between sensors, so it sends just one general alert if it detects water.

Proteus supports Amazon Alexa and IFTTT integration, but the situation is a bit more complicated than with most smart-home devices. First, this integration is available only to owners who enable the Advanced mode. After the 14-day free trial, you need to enter a credit card, but you are charged only for services such as on-demand voice alerts (9¢ per call) and extended alarm and data logging (5¢ per hour). Alexa integration is free but is available only through the Notify Me skill. That means you receive notifications about leaks only on your Echo devices, and you can't create smart-home integrations with other smart devices. You can do that if you are handy with IFTTT, but the process is not your typical two or three clicks. Instead, we found setup to be a lengthy procedure (PDF) involving Webhooks. Proteus does offer step-by-step instructions for all of this, though, and eventually we were able to trigger Lutron and Wyze lights to turn on and off whenever the Aquo was triggered.

Aside from the complicated integration, unlike every other leak sensor we’ve tested, the Aquo doesn't have a dedicated smartphone app. Proteus provides a way to fake an app by bookmarking the web page to your phone's desktop, but the result is not a fluid experience.

Many readers are concerned about how the manufacturing, shipping, and normal use of the products we recommend impact the world. Wirecutter takes that seriously, too, which is why we’ve asked the manufacturers of all our picks to answer some basic questions about the materials they use, the life cycle of their products, and related questions about their products’ overall sustainability. While our product recommendations are based completely on the criteria outlined in How we picked and How we tested, we offer the following information to supplement the decision of any reader who uses environmental impact as a deciding factor in their purchases. We also recognize that the following may not paint a complete picture of a product's supply chain and overall environmental impact.

Smart water-leak sensors allow you to keep tabs on water that's being wasted. That alone can help reduce waste and help you save money. Many of these devices, including our runner-up, the Flo by Moen detector, also allow you to monitor for drastic temperature changes, which are other symptoms of a potentially impending incident that might create preventable damage and waste.

None of the companies we contacted could give us an estimated lifespan, although Proteus did say that, based on its experience, "the sensors should run for 5-plus years." All three companies offer service updates, but in our survey they could not guarantee the length of support once a product is discontinued.

D-Link said it typically "offer[s] support based on the product life cycle, which can be 1-3 years after the discontinuation of the product." We can confirm this policy, since the DCH-S1621KT is our third D-Link pick since 2016. The D-Link DCH-S160 and DCH-S161, both previous picks, have been discontinued. Although D-Link will continue to support software updates on the DCH-S161, the company just announced plans to discontinue the Mydlink Home app, as well as cloud services and software updates for the DCH-S160, on December 30, 2022. That model was released in July 2015 and discontinued in April 2018.

None of our picks offer recycling, although both D-Link and Proteus say they offer incentives to previous and long-time customers. All three of our picks also have a limited warranty of one year.

If you want to monitor multiple areas with one kit: The Orbit B-hyve Smart Flood Sensor uses a plug-in Wi-Fi hub, which you can get only by purchasing sensors in a multipack of three, eight, or 20. That's a substantial up-front investment for a system that doesn't offer any smart-home integration and has an onboard alarm that measured a measly 46 dB—somewhere between a library and a "quiet suburb," according to IAC Acoustics. The sensors do react quickly and are small enough to place anywhere (as long as that spot is within Bluetooth range of the hub), but you’d better be able to reach them, since you can silence them only by squeezing them.

If you’re on a budget: The Govee WiFi Water Sensor is an inexpensive model that supports Alexa integration and has a loud (97 dB) onboard siren. It employs a plug-in Wi-Fi hub, which is packaged with one sensor for about $25; additional sensors are sold individually for $13 each. However, you can silence the alarm only directly on the device itself, and both the hub and the sensors don't send any sort of notice when they lose the Wi-Fi connection and/or power. In fact, when we disconnected them in our tests, the app showed both still connected, with the sensors continuing to indicate full battery life even after 48 hours.

Soon we will start testing the YoLink Water Leak Sensor 2, which features a 4.2-foot water-sensing cable that you can expand up to 10 feet, as well as a 105 dB siren plus support for Alexa and IFTTT. It works with the YoLink Hub (sold separately), which uses LoRa technology and can support up to 200 devices.

The Resideo Wi-Fi Water Leak and Freeze Detector (previously known as a Honeywell model) was a little slower to respond to water and connectivity issues than our picks. It does have a loud (83 dB) audible alarm and dual sensors (one on the device and one at the end of the included 4-foot cable).

The new Eve Water Guard has a lot of the same problems as the old Eve Water Guard: It doesn't provide disconnect notices, it can protect only the 6.5 feet around the outlet you plug it into, and it has an oversize base that blocks the second plug of an electrical outlet. We love the HomeKit support (which also means that if you don't have a HomeKit hub, you’re limited to Bluetooth) and the inclusion of Thread support, but we don't think those features justify the $100 price tag and limited performance.

At 3.5 by 1.12 inches, the Phyn Smart Water Sensor is too big to slide under appliances, which means you’d probably be inclined to add the optional Extension Node ($10) or Sensor Cable ($25). With and without the add-ons, this sensor reacts to water quickly. However, in our testing it took about 24 hours to send an alert regarding power and connectivity issues, which may be problematic. In addition, it doesn't support any smart-home integration, the onboard siren is a relatively soft 67 dB, and you can silence it only by pushing a button on the actual device, which may be difficult for some owners depending on where it's placed.

The Kangaroo Water + Climate Sensor doesn't have an audible alarm, and integration with Amazon Alexa or Google Assistant is a paid perk that costs $10 per month or $99 per year. This device did respond quickly to our tests, sending smartphone notifications when water was present within 11 seconds and issuing disconnection notices within 24 hours. However, you can silence water notifications only by first drying off the device, which may be tricky if it's sitting, say, under a washing machine.

Both the Monoprice Stitch Smart Water Leak/Flood Sensor and the Merkury Smart Wi-Fi Water & Leak Sensor lack enough features for us to recommend either one. They’re both cheap (under $20), they have the same design, they have identical-looking apps (because both were created by Smart Life), and they both don't provide a way for you to dismiss the alarm without physically drying the device off. At least the Merkury has a loud, 85 dB alarm (in contrast to the Stitch's 67 dB) and delivers on its promise of offline notifications—although the alert took about 36 hours to come through in our tests.

Our previous runner-up, the Fibaro Flood Sensor Z-Wave Plus, didn't send us any type of disconnection notices. We also don't love that it uses the SmartThings app, which is basic and doesn't provide a shut-off option for the alarm. The Fibaro Flood Sensor HomeKit model is almost identical, except that it uses Bluetooth, so in our tests it didn't respond as quickly at a distance. Also, if you want alerts when you’re out of the house, you need to have a HomeKit gateway, such as an Apple TV, a HomePod Mini, or an iPad, at home.

Sencentric added a 3-foot sensing cable to the SimpleSENCE Capteur Water Leak Detector. However, both this newer model and the older detector have a not-very-loud alarm (we measured 67 dB—somewhere between a conversation and a dishwasher—on the new version), no smart-home integration, and no disconnection notices. In fact, 48 hours after we tried cutting the power in our tests, the app still claimed that we were protected with a good Wi-Fi connection.

We also dismissed a number of other models from our tests, including the HomeSeer HS-LS100+ Z-Wave Leak Sensor because of its complicated setup process, the LeakSmart Sensor for its high price and slow reaction times, the Grohe Sense because we experienced false alerts and thought the build was too bulky, and the Roost Smart Leak Detector because of issues with battery life.

D-Link DCH-S1621KT: Yes.Flo by Moen Smart Leak Detector: Yes.Proteus Aquo Wi-Fi Water Sensor: Yes.

D-Link DCH-S1621KT: No.Flo by Moen Smart Leak Detector: No.Proteus Aquo Wi-Fi Water Sensor: Yes/no.

D-Link DCH-S1621KT: Yes.Flo by Moen Smart Leak Detector: Yes.Proteus Aquo Wi-Fi Water Sensor: Email addresses are not encrypted; passwords are. Wi-Fi info is not stored on the cloud but directly on the sensor.

D-Link DCH-S1621KT: If not connected, the local alarm will trigger, but there will not be an alert to a customer's mobile device.Flo by Moen Smart Leak Detector: If not connected, the user will not receive alerts via push notification, email, text, or phone call. However, the device will still make an audible alarm when a leak is detected.Proteus Aquo Wi-Fi Water Sensor: The sensor can still be used as a local audible alarm without the cloud. The sensor can also be integrated with open-source systems, such as Home Assistant, which should be extendable to openHAB.

D-Link DCH-S1621KT: No.Flo by Moen Smart Leak Detector: No.Proteus Aquo Wi-Fi Water Sensor: No.

D-Link DCH-S1621KT: No.Flo by Moen Smart Leak Detector: No.Proteus Aquo Wi-Fi Water Sensor: No.

D-Link DCH-S1621KT: Yes, the user will receive an alert about the detector being offline.Flo by Moen Smart Leak Detector: Yes, the user will receive an alert about the detector being offline.Proteus Aquo Wi-Fi Water Sensor: Alert notifications will be sent if the power or Wi-Fi is disconnected, as well as if the sensor cable is unplugged.

This article was edited by Jon Chase and Grant Clauser.

Jared Newman and Michael Brown, Best water leak detectors for smart homes, TechHive, March 18, 2022

Mike Prospero, Best water leak detectors in 2022, Tom's Guide, April 6, 2022

Darwin, The Best of the Z-Wave Water Leak & Flood Sensors, DarwinsDen.com, March 7, 2018

Rachel Cericola

Rachel Cericola is a senior staff writer at Wirecutter who has been covering smart-home technology since the days of X10. Her work has appeared in The New York Times, Wired, Men's Health, USA Today, and others. She hopes her neighbors read this bio because it would explain why she always has four video doorbells running simultaneously outside her home.

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Smart-home sensors can detect leaks, frozen pipes, and open doors so that small problems don't turn into big expenses.

by Jennifer Pattison Tuohy

If you want to power up your smart home, then you need to install smart sensors—tiny detectors that tell other smart devices what to do automatically.

by Rachel Cericola

Smart-home devices can make it easier for you to help an older loved one age safely and securely in their own home.