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Water Rat (Water Level Sensor) - NB-IoT

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Farmo's Water Rat (patent pending) is the best and easiest to set-up tank and trough water sensor on the market. Just throw it in the trough, or tether it to a tank and get low water level alerts on your phone or PC.

**note a brand new version of the Water Rat is coming soon including GPS to make it even easier to keep track of its location**


How it works:

The Water Rat looks simple but has some smart technology inside including a accelerometer tilt sensor to detect movement and a NB-IoT module to send data. When the water level reaches a low point, the Water Rat tilts over and sends an alert. When the water level rises and the Water Rat regains position, another alert is sent to let you know the water is ok again.

The data is sent via NB-IoT which is the long range low-cost version of 4G for IoT devices. The coverage for NB-IoT is approx 30km more from the tower than the 4G network, so if your mobile phone works on site, you can be sure NB-IoT devices will work. Additionally, due to the lower signal frequency of NB-IoT, penetration through buildings and cement tanks is good for this user case.

Design background:

We know from experience a fixed trough sensor has to be incredibly strong to resist the force of a 1-tonne bull. So for the Water Rat we used a different idea of strength inspired by the Ping Fu quote “Bamboo is flexible, bending with the wind but never breaking, capable of adapting to any circumstance". ie If an object is floating, it has no resistance to the force applied to it. The most an angry bull can do is nudge the Water Rat around with its nose.

Secondly, a fixed sensor can require a masonry drill and skills resulting in a permanent or semi-permanent installation. Farms may have more than fifty troughs used in rotation, so that requires a lot of sensors. With Water Rat the idea is that you can just pick up and move the sensor when you move the mob.

Finally for tanks, reaching the bottom and tilting is not ideal so you tether the Water Rat to to the side of the tank. The length of the tether determines the depth at which the Water Rat will tilt over and alert. Most farmers set this up for 50% full or empty, but its up to you.

Monitoring stock water can be made more efficient by technology. The Water Rat will allow much more frequent observations and give you a heads up when something has gone wrong. However, human oversight can never be replaced when animal welfare is at stake.

Sensor Details

  • 9 axis accelerometer
  • GPS location  *new


  • NB-IoT telstra certified module
  • 8000 mAh Li/SOCl2 non-rechargable battery for long-term use
  • Requires a Farmo dashboard subscription to view data and set alerts (provided free of charge)
  • 1m stainless steel wire rope tether (optional) not included

NB-IoT Data Subsrcitpion

  • NB-IoT Telstra data SIM activated when shipped.
  • Requires a data subscription paid yearly.
  • This charge includes free Farmo dashboard access.

Farmo dashboard (included in the data subscription)

  • Visualise data and set alerts on your PC, laptop or phone
  • Display when water level above or below your trigger point
  • Set custom alerts via email (free) or SMS (10c each)
  • Send alerts to different people at different times as required

Application areas

  • Stock water troughs
  • Water tanks
  • Agricultural, Household, Industrial, Smart City, Ag-tech

Care and maintenance

  • Tank or trough should be free of objects that could catch, hold or prevent the Water Rat tilting.


  • All Farmo products include a 12 month warranty as standard.