Get an immediate alert when water is detected
Put a name on the exact sensor, alert the household at any hour, and require a person to inspect the source before clearing the incident.
Best for: Water heaters, washing-machine hoses, sinks, dishwashers, refrigerator water lines, sump areas, and other places where water would collect near a sensor.
Not for: Replacing smoke, carbon-monoxide, sump, or professionally monitored safety systems, or automatically operating an untested main-water valve.
Why this exists
A generic “water detected” message wastes time. The useful alert says where water was found, reaches more than one responsible person, stays visible until acknowledged, and still leaves a clear manual response when the hub or internet is unavailable.
Automatic shutoff can reduce damage, but a valve that cannot reopen, closes on a false report, or has no manual bypass creates a different emergency. Build and test the alert first.
Logic
- Trigger: Any leak sensor reports wet.
- Conditions: None for the first alert. Leak alerts run in Home, Away, Night, and guest modes.
- Action: Send a persistent high-priority notification naming the sensor and location, alert at least two responsible people, and turn on a local indicator if it is safe and useful.
- Wait / timeout: Repeat through a separate backup path only while the incident remains unacknowledged.
- Stop condition: A person inspects the source, stops the water if necessary, and manually clears the incident.
- Manual override: The main water supply and any automatic valve remain manually operable.
What I used
Detect water
THIRDREALITY WL2 Zigbee water leak sensor. Name every sensor for the place a person should inspect.
Stop incoming water
Manual main-water shutoff. Everyone responsible for the home should know the manual valve location.
Reach the household
Persistent phone notification to at least two adults. A local audible alert is useful when phones are muted or away.
See recommended gear for the job-first checklist. I have used both leak sensors. No automatic shutoff product is recommended until I have verified one in this home.
Setup notes
- Name each sensor for the response location, such as “Laundry supply hoses” instead of “Leak sensor 3.”
- Place the contacts where the first escaping water is likely to collect, without blocking drains or creating a trip hazard.
- Confirm wet, dry, unavailable, low-battery, and tamper states before writing the response.
- Send the first alert without time, presence, or mode conditions.
- Include the sensor name, location, detection time, manual shutoff location, and acknowledgment action.
- Deliver the alert to at least two responsible people.
- Test a local audible or visible warning that does not depend on a phone.
- Require manual incident clearing even after the sensor reports dry.
Platform notes
The first requirement is an immediate alert that names the wet sensor. Persistent incident state, local warnings, acknowledgment, valve control, and final-position confirmation are separate capabilities that must each be verified. See the platform guides for broader fit and maintenance tradeoffs.
Amazon Alexa
I could not verify water detection as a universal Alexa routine trigger across leak-sensor integrations. Use Alexa only if the exact sensor appears under When and test the resulting alert with phones and speakers in their normal quiet states. Do not add automatic valve control merely because Alexa can issue a command to a connected device.
SmartThings
Build the first version as a SmartThings Routine only when the sensor exposes water state and the alert identifies the device. An advanced SmartThings Rule can add confirmation and follow-up checks when the required sensor, notification, and valve capabilities are available. Keep incident clearing manual and confirm valve position separately from the close command.
Hubitat
Hubitat Safety Monitor is the natural starting point for monitoring leak sensors and issuing water alerts. Name every device for its physical location. Keep any valve action separate until the installed valve, driver, manual bypass, close confirmation, and reopen procedure have all been tested.
Home Assistant
Home Assistant is a technical fit for combining leak entities, persistent notifications, local warnings, and valve feedback, but I have not personally run it. Verify each integration independently and keep the first implementation alert-only until the complete shutoff path is proven.
Test the alert safely
Follow the sensor’s instructions for testing. Use a damp test surface or cloth on the sensing contacts rather than immersing a device unless its documentation explicitly permits that.
Run the test with:
- Every phone locked and muted as it would normally be overnight.
- Home and Away modes active in separate tests.
- The internet disconnected if local alert behavior is expected.
- The sensor marked unavailable to verify that missing data does not look dry.
- A household member following the message to the correct shutoff.
Retest after moving a sensor, changing its battery, changing notification settings, or editing the automation.
Optional automatic shutoff
Do not add valve control until alert-only behavior is dependable. Before enabling automatic closure:
- Have the valve installed in a manner appropriate for the plumbing and local requirements.
- Verify it can close the actual valve fully and report the final position.
- Label and test the manual bypass.
- Decide which sensors may close the main supply and which should only alert.
- Use a short, tested confirmation rule without delaying the first notification.
- Notify on the close command, successful closure, failure, and unexpected reopening.
- Require a person to inspect the home before reopening.
- Keep freeze protection, fire-suppression supply, boilers, irrigation, and other water-dependent systems in the safety review.
Do not automatically turn off a water heater or other appliance unless its manufacturer instructions and a qualified professional support that exact response.
Advanced features
Add a sensing cable
A remote probe or sensing cable can cover a wider edge behind an appliance or around a tank. Test every section that must detect water and keep the control body above the likely water line.
Escalate only when nobody acknowledges
Send the immediate alert to the primary household group. If nobody acknowledges it, use one independent backup route to a trusted person. Avoid endless repeated notifications that hide new information.
Track sensor health
Treat low battery, unavailable, and stale reports as maintenance problems. A silent sensor must not appear healthy just because it is not reporting wet.
Failure modes
- Alert does not identify the source: Rename the sensor for a physical location and include that name in every message.
- Only one person receives the alert: Add a second responsible recipient and test both locked phones.
- Sensor reports dry after being moved: Keep the incident open until a person inspects and clears it.
- Condensation causes nuisance alerts: Move the sensor without moving it away from the first likely leak path, or use a remote probe suited to the location.
- Water misses the contacts: Observe drainage paths and use a tray, probe, or sensing cable where appropriate.
- Sensor becomes unavailable: Create a separate health alert and inspect the device promptly.
- Automatic valve does not close: Report the failure clearly and direct the household to the labeled manual shutoff.
- Automatic valve closes unexpectedly: Keep manual bypass instructions at the valve and disable automation until the cause is understood.
FAQ
Should one leak sensor automatically close the main water valve?
Start with immediate alerts. Add automatic shutoff only after the valve, manual bypass, sensor behavior, and safe reopen procedure have all been tested with the household.
Does a dry sensor mean the leak is resolved?
No. A dry report can mean water moved away from the contacts or the sensor was picked up. Require a person to inspect the area and clear the alert manually.
Where should leak sensors go first?
Start where a hidden or pressurized leak would cause damage quickly, such as the water heater, washing-machine supply hoses, under sinks, and near a dishwasher or refrigerator water line.