Water Leak Sensor Not Detecting or Alerting

Common Causes

• The sensor's metal contact probes are dirty or corroded
• The sensor is placed incorrectly and the probes are not making contact with the surface
• Battery is low or dead, preventing the sensor from transmitting alerts
• The sensor is out of Zigbee range from the Aqara hub
• Notifications are disabled in the Aqara Home app or on your phone
• Automations linked to the sensor are misconfigured

Fix 1: Check Sensor Placement

The Aqara Water Leak Sensor detects water through two metal contact probes on the bottom of the device. Both probes must be in direct contact with the surface where water would pool.

1. Flip the sensor over and inspect the two metal probes. They should be clean, free of dust, and not corroded.
2. If the probes are dirty, wipe them with a dry cloth or gently clean them with a cotton swab dipped in rubbing alcohol.
3. Place the sensor flat on the floor near potential leak sources such as under a washing machine, water heater, dishwasher, or sink cabinet.
4. Make sure the probes sit directly on the floor surface, not on top of a rug, mat, or uneven surface that would lift them off the ground.

Fix 2: Test the Sensor Manually

1. Dip your finger in water and touch both metal probes on the bottom of the sensor simultaneously.
2. The sensor's LED should blink and you should receive an alert in the Aqara Home app within a few seconds.
3. If the LED blinks but you do not receive a notification, the issue is with your notification settings or automations, not the sensor itself.
4. If the LED does not blink at all, the battery is likely dead or the sensor hardware has failed.

Fix 3: Replace the Battery

1. Use a coin to twist open the battery compartment on the back of the sensor.
2. Remove the old CR2032 battery.
3. Insert a fresh CR2032 battery with the positive side (+) facing up.
4. Close the battery cover. The LED should flash once, confirming the sensor has power.
5. Check the Aqara Home app to verify the sensor comes back online. Battery-powered Zigbee sensors can last 1 to 2 years, but battery life varies based on how often the sensor triggers.

Fix 4: Verify Notifications Are Enabled

Even if the sensor detects water correctly, you will not receive alerts if notifications are turned off.

1. Open your phone's Settings and navigate to Notifications.
2. Find the Aqara Home app and ensure notifications are enabled, including banners, sounds, and lock screen alerts.
3. In the Aqara Home app, go to Settings and check that push notifications are turned on.
4. Open the Water Leak Sensor's device page and verify that its alert/notification toggle is enabled.

Fix 5: Check or Recreate Automations

If you are relying on an automation to alert you or trigger other devices when water is detected, verify the automation is set up correctly.

1. In the Aqara Home app, navigate to Automations.
2. Find the automation linked to the Water Leak Sensor and confirm the trigger condition is set to "Water Leak Detected" or "Water Alarm."
3. Verify that the action (send notification, sound alarm on hub, turn off smart valve, etc.) is correctly configured.
4. Make sure the automation is enabled (toggled on). Disabled automations appear grayed out.
5. If the automation seems correct but still does not trigger, delete it and create a new one from scratch.

Fix 6: Re-Pair the Sensor

If the sensor is not detected in the app at all or shows as "unavailable," re-pair it to your hub.

1. Remove the sensor from the Aqara Home app by going to its device page, tapping Settings, and selecting Remove Device.
2. Press and hold the reset button on the sensor for 5 seconds until the LED blinks rapidly.
3. Add it again through the app by tapping + and following the pairing instructions.
4. After re-pairing, you will need to recreate any automations that were linked to the sensor.

Prevention Tips

• Test your water leak sensors every few months by touching the probes with a wet finger to confirm they still alert.
• Replace the battery proactively once a year rather than waiting for it to die — a dead battery means no leak alerts.
• Place sensors in every high-risk area: under water heaters, washing machines, dishwashers, sinks, and near sump pumps.
• Pair the water leak sensor with an Aqara smart water valve (if available) to automatically shut off the water supply when a leak is detected.