In order for Flo to register any water usage, water has to pass through the valve which spins the internal turbine and registers water flow.
If you see no movement on your city meter but do see some water consumption on your Flo by Moen app, it’s possible that your city feed may be flowing back and forth slightly - also known as "backflow."
Flo is not able to count reverse consumption, and as a result, any water flowing back or forth through Flo will be registered as consumption, and add towards your daily goal. As the water may flow back and forth in small amounts throughout the day, the meter will zero out and seem like no water was used.
This reverse flow is referred to as backflow and can be prevented by the installation of a check-valve on the main water line which will only allow water to flow in one direction. Check valves should be installed before the Flo by Moen device for optimal backflow prevention and accuracy of the Flo by Moen device.
To test for backflow, you will need to actively monitor your city meter to see if the needle spins backward at any point. Backflow can occur at random, and it may take a few attempts at monitoring the meter observe its occurrence.
If you see this occurring on your supply line, we recommend contacting your water municipality to give them notification of the issue as certain categories of backflow can be considered a contamination hazard.