This week, I added a bunch of Aqara Water Leak Sensors to my home assistant setup.

Pairing the Aqara Water Leak Sensor with Home Assistant

The first hurdle was how to trigger pairing mode of the Aqara Water Leak Sensor. The manual only describes this process for their own hub / app combination. I run Home Assistant with a ZigBee stick and would rather not add a hub for each device maker. Turns our the solution is simple: Press on the top of the sensor till a blue light just below the water drop starts flashing. This switches the device into pairing mode. I was able to pair the sensor as usual in the Zigbee panel of Home Assistant.

Rename the Sensors

The names chosen for the actual sensor entities were a bit random and hard to parse for me. Hence, I renamed the sensor entities to something like binary_sensor.water_leak_detector_kitchen_sink in the Home Assistant UI. This makes subsequent references to them from YAML code a lot easier.

Test the sensor

When initially testing the sensor, they failed to detect water even when submerged for a few minutes. When I repeated the same test a few minutes later, they detected water in much smaller volume instantly. Not sure why this is. Could be that the sensor calibrates itself after startup and needs some time to do so.

Group the sensors

When thinking about water leak notification, I don’t actually care which sensor is detecting a leak. I can look that up in the Home Assistant UI whenever I want. Hence, I grouped the devices into one meta sensor using the Binary Sensor Group platform like so in my configuration.xml:

  - platform: group
    name: Water Leak
    device_class: moisture
      - binary_sensor.water_leak_detector_kitchen_sink
      - binary_sensor.water_leak_detector_main_bath_sink_right
      - binary_sensor.water_leak_detector_main_bath_sink_left
      - binary_sensor.water_leak_detector_main_bath_toilet
      - binary_sensor.water_leak_detector_utility_room
      - binary_sensor.water_leak_detector_washing_machine

This creates a new sensor named Water Leak with the entity id binary_sensor.water_leak. This sensor will detect a leak whenever any one of the grouped sensors does so.

Setup an Alert

This new group then allows me to send alerts to my phone using the Alert platform like so:

    name: Water leak detected
    message: Water leak detected
    done_message: Water leak no longer detected
    entity_id: binary_sensor.water_leak
    state: "on"
    repeat: 1
      - mobile_app_pixel_4_xl

This will send a notification to my phone (entity mobile_app_pixel_4_xl) once a minute while a leak is detected. It will send the “all clear” notification when the leak is no longer detected. This might be a bit excessive, but better safe than sorry :-).