Water damage is one of the most common and costly home insurance claims. These smart water shutoff valves and leak sensors can automatically close your main supply or alert you the moment a leak is detected—across every budget.
Water damage is one of the most common and costly home insurance claims, but a smart water shutoff valve can automatically close your main supply the moment a leak is detected—turning a potential disaster into a notification. This guide covers the best whole-home automatic shutoff valves and complementary leak sensors across price tiers.
Not all "smart water" devices do the same thing. The key distinction is between automatic shutoff valves that physically close your main water line when they detect a problem, and leak sensors that alert you but can't stop the flow themselves. Whole-home shutoff valves typically require professional installation and cost $500–600, while spot sensors are cheap DIY units you place under sinks or near water heaters.
Here's how the top options compare.
The Moen Flo is a professional-grade whole-home water monitor that installs in-line on your main water supply. It detects leaks via flow rate analysis and can automatically shut off your water when it senses a problem.1 Beyond emergency shutoff, it tracks daily water usage and supports Alexa and Google Assistant for voice commands and alerts.1
At $500–600, it's a serious investment, but it's the closest thing to having a plumber on call 24/7. The Flo monitors your entire plumbing system continuously, learning your usage patterns to distinguish between a running shower and a slow leak behind a wall.6
Best for: Homeowners who want active, automatic leak prevention and don't mind paying for professional installation.
The Phyn Plus is the other premium in-line automatic shutoff valve, priced in the same $500–600 range as the Flo. What sets it apart is its daily system health tests—it runs automated checks on your plumbing each day to catch micro-leaks and pressure issues before they become visible problems.2
It also offers detailed consumption analysis, breaking down water use by fixture, and supports Alexa, Google Assistant, and IFTTT for broader smart home integration.2
Best for: Data-minded homeowners who want the deepest insight into their plumbing system's health, not just emergency shutoff.
Both are premium in-line valves that automatically shut off your water during a catastrophic leak. The Flo emphasizes safety and usage tracking with a straightforward approach; the Phyn adds daily diagnostic health tests that give you a more granular picture of your plumbing over time. If you want set-it-and-forget-it protection, the Flo is simpler. If you want to understand exactly what's happening in your pipes, the Phyn is the stronger choice.
The Flume 2 takes a completely different approach: instead of cutting into your pipes, it straps onto your existing water meter. There's no plumbing required, making it a true DIY install that takes minutes.3
It tracks whole-home water usage and sends leak alerts to your phone, with Alexa support for voice queries.3 At $199–249, it's roughly half the price of a Flo or Phyn—but the trade-off is that it cannot shut off your water. It will tell you there's a leak, but you'll have to turn off the valve yourself.
Best for: Renters, budget-conscious homeowners, or anyone who wants usage monitoring and leak alerts without paying for professional installation.
The Eve Water Guard is a premium spot sensor designed specifically for the Apple ecosystem. It supports Thread connectivity for a fast, reliable mesh network and works natively with Apple HomeKit.4 When it detects water, it sounds a loud onboard siren and sends a notification to your phone.
The expandable sensor cable lets you extend coverage across a wider area—useful under a washing machine or along a baseboard near a water heater.4 At $80–110, it's a mid-range pick that won't shut off your water but will make sure you hear about a leak fast.
Best for: Apple HomeKit users who want a premium, Thread-enabled spot sensor with a loud siren.
At around $18, the YoLink Water Leak Sensor 4 is the most affordable option here—and honestly, at that price, you can buy several. It uses dual-probe sensing for reliable detection and sounds an 87 dB siren when water touches it.5
Its long-range wireless connectivity means you can place sensors in basements or crawl spaces far from your router and still get alerts.5 It won't shut off your water, but for targeted coverage under sinks, behind toilets, or near a water heater, it's hard to beat the value.
Best for: Budget-conscious shoppers who want to cover multiple leak-prone spots for the price of one premium sensor.
A note on how we make money: AskBuy earns a commission when you buy through our links. That doesn't change what we recommend—we pick based on what's actually best for each situation.
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