A leak sensor alerts when water reaches its probe; an automatic shutoff system can also close a valve on the main supply when it detects a leak or unusual flow. Sensors are simpler to place near risk points, while a shutoff adds plumbing work and must be installed and tested correctly. Compare the smart water shutoff guide for monitoring and installation checks.
Leak detection and water shutoff are related functions, but they are not the same product. Decide whether you need a warning at a few risk points or a device that can close the main supply.
Side by side
| Leak sensors | Automatic shutoff system | |
|---|---|---|
| Main response | Alarm or app notification | Notification and, on supported models, valve closure |
| Coverage | Each sensor covers its placement area | Main-line valve plus any paired remote sensors |
| Installation | Place and pair sensors | Plumbing work at the main line and system setup |
| Detection | Water at probe or cable | Sensor input, flow monitoring or both, depending on model |
| Failure checks | Battery, signal and alert path | Valve exercise, power backup, sensor, flow settings and manual override |
An automatic valve’s flow monitoring can trigger false alerts if its settings do not reflect the home’s normal use. Check the maker’s instructions for calibration, tests and how to reopen the valve after a trip.
Choose the coverage you need
Choose standalone sensors if you want targeted alerts around specific appliances and can respond quickly. Choose a main shutoff when you want the system to have a way to stop supply, and confirm the valve, plumbing size, power backup and manual override. For installation details, see our smart water shutoff guide.
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Common questions
Do leak sensors shut off the whole house?
Some work only as alerts; others pair with a compatible valve. Verify whether the specific kit includes a valve and what it controls.
Where should I place leak sensors?
Follow the system manual and prioritize areas with water connections or appliances, such as under sinks, near a water heater or by a washing machine.
Will an automatic shutoff work during a power or internet outage?
Backup power, local detection and alert delivery vary by model. Check the manual for behavior during an outage.