Leak detectors with automatic water shutoff
A shutoff valve is the only device here that stops the water instead of reporting it. It is also powerless against the water this site is mostly about.
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Everything else in this section reports. A shutoff valve acts. When a supply line fails it can deliver hundreds of gallons an hour for as long as nobody is home, and closing the main is the only intervention that changes the outcome.
What a shutoff valve protects against, and what it does not
| Water source | Shutoff valve helps? |
|---|---|
| Burst washing machine hose | Yes — this is the headline case |
| Split water heater connection | Yes |
| Pipe freeze and burst while away | Yes, and it may warn on temperature first |
| Slow drip inside a wall | Yes, via the daily pressure test |
| Groundwater through the foundation | No. Not on your supply line |
| Sump pit overflow | No |
| Storm water through a window well | No |
Three of those seven are the reason this site exists, and a shutoff valve does nothing for any of them. For those, the answer is a working pump, a backup, and the waterproofing section.
Quick picks
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 |  Flo by Moen Smart Water Shutoff (900-006)Monitors flow, pressure and temperature on the main and closes the valve on a burst — plus a daily micro-leak test. | Whole-home supply protection | 8.7 | Check price on Amazon #ad we earn a commission · Amazon shows the current price |
| 2 |  YoLink Water Leak Sensor 4Pair the sensors with a motorized valve controller in the same ecosystem for a lower-cost shutoff path. | Triggering a shutoff without replumbing | 8.5 | Check price on Amazon #ad we earn a commission · Amazon shows the current price |
Scores are ours and editorial, not lab measurements — see how we pick. Tap a row for the full write-up.
Flo by Moen Smart Water Shutoff (900-006)
Monitors flow, pressure and temperature on the main and closes the valve on a burst — plus a daily micro-leak test.
#ad we earn a commission · Amazon shows the current price
| Type | Whole-home water monitor with a motorized shut-off valve |
|---|---|
| Pipe compatibility | 1" to 1-1/4" pipe diameter |
| What it measures | Flow, pressure and temperature on the main line |
| MicroLeak | Daily pressure test that can find leaks as small as a drop per minute |
| Power | Standard AC adapter, 100 to 240 VAC, 10 ft cable |
| Hub | None required; Wi-Fi only |
| Operating temperature | 32 to 140 F |
| Warranty | One year, limited |
This is the most capable device in this whole section and the most frequently misunderstood. It watches your incoming supply and shuts it off when the pattern says something has burst. For a washing machine hose, a split heater connection or a pipe that lets go while you are away, nothing else comes close.
The micro-leak test is the underrated feature. A daily static-pressure check catches the slow drip inside a wall that would otherwise be found by a stain on the ceiling eighteen months later.
Be completely clear on the limit: groundwater entering through a foundation wall or a sump pit is not on your supply line. The valve will close and the water will keep coming.
What it gets right
- Closes the main automatically, which is the only thing that stops a burst supply line
- The daily pressure test can find leaks as small as a drop per minute, long before damage
- No hub required; connects to Wi-Fi directly
Where it falls short
- Fits 1 to 1-1/4 inch pipe and generally needs a plumber to install
- Needs mains power at the valve
- One-year limited warranty is short for a device of this cost
Specifications from Flo by Moen 900-006 product page, Flo by Moen distributor listing.
YoLink Water Leak Sensor 4
Pair the sensors with a motorized valve controller in the same ecosystem for a lower-cost shutoff path.
#ad we earn a commission · Amazon shows the current price
| Type | LoRa water leak sensor |
|---|---|
| Hub | A YoLink hub with an internet connection is required for app and alert features |
| Range | Long-range LoRa, quoted up to about 1,000 ft in practice |
| Local alarm | 105 dB on the sensor itself |
| Battery life | 5+ years, per YoLink |
| Ingress rating | IP66 |
| Extra | Built-in freeze warning |
The component approach has a genuine advantage: inline monitors see only what passes the main, while sensors see water where it lands. A sensor-triggered valve closes on a leak that an inline monitor might read as ordinary consumption.
It is also more to get right. Test the whole chain — wet sensor, valve closes — rather than assuming the automation works.
What it gets right
- Sensors go where water actually appears, rather than only at the main
- Cheaper route to automatic shutoff than a full inline monitor
- Local siren and long range as well
Where it falls short
- You are assembling a system rather than buying one
- Shutoff speed depends on where the sensor is relative to the leak
- Automation depends on hub and app configuration being right
Specifications from YoLink Water Leak Sensor 4 product listing, YoLink leak sensor specification summary.
Before you buy
- Check your pipe size and material at the point where the main enters. Inline monitors are specific about what they fit.
- Check there is power nearby. These valves need a permanent supply at the valve location.
- Budget for a plumber unless you are confident cutting into the main and are sure of local rules.
- Ask your insurer. Some carriers discount for a monitored automatic shutoff, which changes the arithmetic.
Questions people ask
Do automatic water shutoff valves lower insurance?
Some carriers offer a discount for a monitored automatic shutoff system; fewer offer anything for plain sensors. It varies by insurer and state, so ask yours directly before counting on it.
Can I install a smart shutoff valve myself?
Only if you are comfortable cutting into the main supply and local rules permit it. Most installations are a plumber's job, and that cost belongs in your comparison.
Will it stop my basement flooding?
Only if the flooding comes from your plumbing. Groundwater, storm water and sump overflow are unaffected — those need drainage, a pump and a backup.
What happens during a power outage?
The valve stays in its current position and the monitoring stops. Some units carry a small backup battery for the valve actuator; check the specification if that matters to you.
Sources
Read next
Flo by Moen smart water shutoff review
The most capable device on this site, aimed at a problem that is not quite the one this site is about. Worth understanding before you spend.
The best water leak detectors
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The best Wi-Fi water sensors
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Sensors are cheap and placement is free. Getting the second one right is what turns a gadget into protection.
The best basement water alarms
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