Tracking water for duplex with one meter

[Danielle Thompson]

We have a duplex and are working to make it legal. The city doesn’t require us to have two water meters but we’d like to track it some way so we can charge tenants based on their usage if possible instead of a50/50 split. Are there any systems you have used to track water usage for separate units when you only have a single meter?

We have one mainline from the city and then when it gets to the house we have separate lines.