I need a water leak sensor that shuts off the main valve automatically.

An automatic water leak shut-off system requires a sensor-triggered valve controller installed on your main water line.

Protecting your home from major floods involves pairing remote leak sensors with a motorized shut-off valve. Depending on your budget and whether you want a plumber or a DIY clamp-on device, several top-tier choices exist on the market.

Popular Automatic Water Shut-Off Systems

Watch this video to see how a long-range wireless leak detection and automatic shutoff system works in a real home:

9:06 Water Leak Detection and Automatic Shutoff System 7K views  · 1 year ago YouTube · From one DIY to another

Types of Shut-Off Systems

Inline Motorized Ball Valves Brands like U.S. Solid Go to product viewer dialog for this item. and iSpring Go to product viewer dialog for this item. require a plumber to cut into your main 3/4-inch or 1/2-inch water pipe. Once installed, a signal from any wet floor sensor instantly triggers the mechanical valve to close.[1][2]

To help narrow down the best choice, let me know:

• Do you prefer a DIY clamp-on unit or an inline plumbed valve?
• Do you want smart home (Wi-Fi/app) notifications or a standalone system?

Yes — you want a whole-home automatic water shutoff system, not just a leak alarm. It installs on the main water line and can close the valve when it detects a serious leak.

My top picks

• Moen Flo Smart Water Monitor & Shutoff - $606.00 (Home Depot + others)

• Phyn Plus 2nd Gen Smart Water Assistant + Shutoff - $575.98 (Home Depot + others)

• Moen Flo Smart Leak Detector - $58.36 (Moen + others)

• Best overall: Moen Flo Shutoff — monitors water flow/pressure throughout the house and can automatically shut off the main supply. You can also add individual leak sensors in places such as the laundry room, attic, or under sinks. Moen confirms that a Flo Detector can trigger the main shutoff automatically when it senses water.

• Strong alternative: Phyn Plus — monitors the whole home's plumbing and can automatically shut off the water when it detects a leak.

• If you already have a compatible shutoff: individual Moen leak detectors are useful for catching localized leaks and triggering the shutoff.

• Resideo L5 is another good professional-install option. It connects to the main supply and can shut the water off when its sensor cable or compatible leak detector senses water. Its sensor coverage can be expanded substantially.

Important: the main shutoff requires cutting into/installing on your home's main water line, so I'd normally have a plumber install it. You'll also want to check whether your main line is ¾", 1", or 1¼" before buying.

If you tell me your main pipe size (¾", 1", or 1¼") and your budget, I can narrow this down to the best system and find the best current price.

To automatically shut off your main water valve when a leak is detected, you need an in-line smart water shut-off valve system (often paired with remote puck sensors). Unlike standalone leak detectors that only sound an alarm, these systems tie directly into your main water supply line to stop floods instantly. [1][2][3][4]

Top systems on the market balance whole-home protection, app controls, and automatic shut-off capabilities:

Widely considered the gold standard. It installs on your main water line, tracks daily usage, runs daily micro-leak tests, and automatically cuts off the water if it senses a burst pipe or unusual continuous flow. You can also bundle it with remote puck sensors for high-risk spots (like under sinks). Check pricing and options at Home Depot. [1][2][3]

Uses high-precision ultrasonic pressure wave analysis to learn your home's water habits and detect tiny leaks anywhere in your plumbing. It features an automatic shut-off valve and an interactive display screen.

A budget-friendly, highly reliable DIY option. It uses a motorized valve attachment that clamps directly over your existing main quarter-turn ball valve (meaning zero plumbing cuts required) and pairs wirelessly with long-range remote leak sensors to shut the water off instantly.

A straightforward, hardwired-style control unit with an automatic 3/4-inch motorized ball valve and local puck sensors. It's great if you want a dedicated local system without relying heavily on Wi-Fi apps. View details at Lowe's.[1]

To help narrow down the best fit, tell me:

• What is the diameter and material of your main water pipe (e.g., 3/4-inch copper, 1-inch PEX)?
• Do you prefer a professional-grade whole-house monitor (like Moen/Phyn) or an easy DIY add-on valve (like YoLink)?
• Do you have an electrical outlet near your main water shut-off?

Yes — what you want is a whole-home leak detection system with an automatic main-water shutoff valve, rather than just a standalone leak sensor.

My top picks

• Phyn Plus Smart Water Assistant + Shutoff (2nd Gen) - $579.99 (Phyn)

1. Phyn Plus 2nd Gen — best overall

• Installs directly on the main water line.

• Detects leaks by analyzing changes in water pressure.

• Automatically shuts off the main water supply when it detects a leak.

• Current price: about $580.

• No separate floor sensors are required for whole-home plumbing monitoring.

• MOEN Flo 3/4 in. Shutoff Whole-Home Leak Detector - $559.00 (The Home Depot)

2. Moen Flo — excellent alternative

• Monitors flow, pressure and temperature continuously.

• Can detect extremely small leaks and automatically shut off the water.

• App lets you shut the water off remotely.

• Current retail pricing is roughly $560–$625, depending on pipe size.

• You can add individual Moen leak detectors in places such as under sinks, behind toilets, or near the washing machine; those sensors can also trigger the main shutoff.

• YoLink FlowSmart All-in-One Smart Water Meter - $459.99 (YoLink)

3. YoLink FlowSmart — worth considering if you want sensor coverage

• Combines water-flow monitoring with automatic shutoff.
• YoLink also offers separate wireless leak sensors, which is useful for detecting water outside the main plumbing, such as a leaking washing machine or water heater.
• Some versions are designed to continue operating even if Wi-Fi/internet goes down.

What I'd buy

For a typical house, I'd choose Phyn Plus or Moen Flo + a few strategically placed floor sensors. The main valve protects against things like burst pipes and continuous water flow, while floor sensors catch leaks where water is escaping from a fixture.

One important detail: before buying, determine the size of your main water line — commonly 3/4", 1", or 1-1/4". The valve has to match your plumbing configuration, and installation is generally a plumber job. Phyn specifically notes that adapters may be required depending on the existing plumbing.

If you tell me your main pipe size (3/4", 1", etc.) and your budget, I can narrow this down to the best 2–3 systems for your house and current prices.

When you want a setup that automatically shuts off your main water valve, you are generally looking at one of two approaches: an all-in-one smart whole-house valve (which monitors flow and pressure directly on the main line) or a wired/wireless kit that pairs localized puck sensors with a motorized valve controller attached to your main pipe.

Top-rated options tailored to different budgets and installation styles include:

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• Type: Whole-house inline monitor and automatic valve.
• How it works: Installed directly onto your main water supply line. It doesn't rely strictly on standalone floor pucks; instead, it uses internal pressure and flow sensors to track water usage and detect micro-leaks (as small as a single drop per minute) anywhere in the home, shutting off the water automatically if a major anomaly is found. You can check out options and pricing directly on the Moen Shop.
• Pros: Comprehensive 24/7 protection, smartphone app control, works with optional remote disc sensors for specific high-risk zones.[1]

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• Type: Traditional sensor-to-valve control system.
• How it works: A motorized 3/4" NPT ball valve clamps onto your main supply line and connects via cable to a control module. It comes with physical floor sensors placed near vulnerable spots (like a water heater or washing machine) that trigger an immediate shut-off and alarm the second they touch moisture. You can view details on the Home Depot iSpring LS43 Page.
• Pros: Highly affordable, straightforward local wired triggering, supports multiple add-on sensors.[1]

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• Type: Premium, ultra-sensitive whole-house flow system.
• How it works: Professional-grade bronze valve installed at the main entry point that senses flow down to a half-ounce per minute. Highly favored by high-end residential insurance providers. More information is available on the FloLogic Store.
• Pros: Incredible sensitivity, battery backup, rugged build quality.[1]

To help narrow down the best choice, let me know:

• What is the diameter of your main water pipe (e.g., 3/4 inch, 1 inch)?
• Do you prefer a smart/Wi-Fi app-enabled system or a standalone local sensor kit?
• Are you comfortable cutting into your main water line for an inline install, or do you need a clamp-on actuator?

Yes — you want a whole-home automatic water shutoff system, not just a moisture alarm. These install on your main water line, detect abnormal flow/leaks, and close the valve automatically.

My top picks

• MOEN Flo 1 in. Smart Water Monitor & Automatic Shutoff - $747.98 (The Home Depot)

1. Moen Flo — best overall. It continuously monitors flow and pressure, can detect leaks as small as a drop per minute, and automatically shuts off the main water supply when it detects a problem. It also provides phone alerts and lets you shut the water off remotely.

• Phyn Plus 2nd Gen Smart Water Assistant + Shutoff - $539.98 (The Home Depot)

2. Phyn Plus — excellent leak detection. It uses pressure-wave analysis and has a built-in shutoff valve, so it can detect abnormal water events and automatically close the main supply. Current manufacturer price is about $580.

• YoLink FlowSmart All-in-One Smart Water Meter - $629.99 (YoLink)

3. YoLink FlowSmart — worth considering if you want offline capability. The system combines leak detection, water monitoring and automatic shutoff, and the manufacturer says it can continue operating during loss of Wi-Fi/internet.

What I'd buy

For a typical house, I'd lean toward the Moen Flo. It is a purpose-built whole-house system, has strong leak-detection capabilities, and doesn't require you to scatter individual sensors throughout the house for basic whole-home monitoring.

Important: you'll need to know the size of your main water pipe (typically ¾", 1", or 1¼") and have an electrical outlet/Wi-Fi near the installation point. These are normally installed inline on the main water supply, and professional plumber installation is recommended.

If you tell me your main pipe size (or send me a photo of your water meter/main shutoff) and whether you want DIY or plumber installation, I can narrow this down to the best specific model and current price.

Yes — you want a whole-home leak detection system with an automatic main shutoff valve, rather than just a standalone water sensor.

My top pick: Moen Flo

• MOEN Flo 1 in. Shutoff Whole-Home Leak Detector and Automatic Water Shutoff Valve - $608.00 (The Home Depot)

The Moen Flo Smart Water Monitor & Shutoff is probably the best fit. It installs inline on your home's main water supply and continuously monitors flow, pressure, and temperature. It can automatically shut off the entire home's water when it detects a serious leak.

You can also add separate Moen Flo Detectors under sinks, near the water heater, washing machine, sump area, etc. Those sensors can be configured to trigger the main Flo valve automatically when they detect actual water on the floor.

Other good options

• Phyn Plus 2nd Gen Smart Water Assistant + Shutoff - $539.98 (The Home Depot)

• Kohler H2Wise+ Smart Water Monitor & Automatic Shutoff - $540.03 (The Home Depot)

• GROHE Sense Guard Smart Water Controller - $418.00 (The Home Depot)

• YoLink Automatic Water Leak Detection & Shut-Off Starter - $299.99 (Walmart - YOSMART)

• Phyn Plus — excellent pressure-based leak detection and automatic shutoff.

• Kohler H2Wise+ — another strong whole-home option, powered by Phyn technology.

• GROHE Sense Guard — continuously monitors the plumbing and automatically shuts off when it detects a major problem.

• YoLink — worth considering if you want multiple wireless floor sensors and a less expensive setup.

One important detail: before buying, you'll need to know the size of your home's main water pipe (commonly 3/4", 1", or 1-1/4"). The Moen Flo, for example, comes in different sizes. Professional installation is recommended because the valve is installed directly into the main water line.

If you tell me your main pipe size, your budget, and whether you want Wi-Fi/app control, I can narrow this down to the best 2–3 choices.

The best systems for automatic shut-off feature an integrated motorized ball valve and remote sensors that trigger closure the moment moisture is sensed. Whole-house automatic shut-off systems range from $100 to over $2,100 depending on whether you need a wired kit or a smart wireless ecosystem.

Watch this video overview to see how water sensors integrate with smart valve controllers to stop leaks automatically:

9:39 A Must-have Smart Home Device For Every Homeowner!67K views  · 1 year ago YouTube · Shane Whatley

Top Automatic Shut-Off Systems

Popular Smart Alternatives

Add to list Uses a long-range wireless valve controller paired with wireless puck sensors that shut your main valve off upon contact.

Add to list Integrates with modern smart home platforms via Matter to automate shut-off actions when paired with compatible water sensors.

If you can tell me the pipe size (e.g., 3/4-inch or 1-inch) and whether you prefer a wired standalone kit or a smart Wi-Fi/wireless setup , I can help you pick the exact model.

An automatic water shut-off system combines remote leak sensors (placed near appliances, toilets, or water heaters) with a motorized valve installed directly on your main water line. When a sensor detects moisture, it instantly signals the main valve to close.

Top-rated systems on the market balance whole-home protection, ease of installation, and reliability:

• Type: Inline professional install (replaces a section of your main pipe).

• Why it's great: Highly recommended by plumbers and insurance providers. It uses high-definition pressure analysis to monitor your entire plumbing system for micro-leaks and major bursts alike, shutting off the water automatically and offering great app reporting. You can check out details on the Phyn Plus Official Site.

• Type: Inline professional/plumber install.

• Why it's great: Proactively measures daily water consumption, pressure, and temperature. It features automatic or manual shut-off via smartphone and runs daily automated "health tests" on your plumbing. Available to explore on Amazon - Moen Flo.

• Type: Retrofit motorized valve (clamps onto your existing main ball valve) or inline smart valve paired with wireless puck sensors.

• Why it's great: Uses long-range LoRa wireless tech (great for basements/crawlspaces where Wi-Fi struggles) and doesn't always require cutting into your main water pipes if you use the valve operator. Highly customizable with individual puck sensors placed around the house.

To help narrow down the best choice, let me know:

• Is your main water shut-off a lever-style ball valve or an old-school round gate valve?
• Do you prefer a DIY-friendly retrofit (attaches over your current valve) or a professional inline system that cuts into the pipe?
• Do you use a specific smart home ecosystem like Alexa, Google Home, or Apple HomeKit?

Yes — you want a whole-home automatic water shutoff system, not just a leak alarm. It installs on the main water line and closes the valve when it detects a leak.

My top picks

• MOEN Flo 1 in. Shutoff Whole-Home Leak Detector - $608.00 (The Home Depot)

1. Moen Flo — best overall

• Monitors the home's water flow and pressure 24/7.

• Can automatically shut off the main water supply.

• Can detect very small leaks and sends phone alerts.

• You can add separate floor/room leak detectors that trigger the main shutoff.

• Available in ¾", 1", and 1¼" versions, so you'll need to match your main pipe size.

• Professional installation is recommended.

• Phyn Plus 2nd Gen Smart Water Assistant + Shutoff - $539.98 (The Home Depot)

2. Phyn Plus — excellent alternative

• Built-in automatic shutoff valve.

• Uses pressure-wave analysis to identify leaks.

• Can shut off the water automatically when a leak is detected.

• iSpring LS43 Automatic Shut-Off System - $149.99 (Lowe's)

3. iSpring LS43 — budget option

• Around $150.
• Includes leak sensors and an automatic valve.
• Much cheaper than Moen/Phyn, though it's more of a straightforward leak-sensor/shutoff system rather than a sophisticated whole-home water monitor.

What I'd buy

For a typical house, I'd choose the Moen Flo. The important advantage is that it can detect abnormal water usage from the plumbing itself, while additional Moen leak sensors can detect water escaping from places such as a water heater, washing machine, toilet, or refrigerator and trigger the main shutoff.

Before buying, check the diameter of the main water line where it enters your house (¾", 1", or 1¼"). If you tell me your pipe size and whether you're on a well or city water, I can narrow it down to the best exact system and current price.