Billing city utilities (garbage sewer/water) back to tenants?

[Brandon Capelle]

I own a duplex in Minneapolis, MN and would like to charge the city utilities back to the tenants. Water/sewer isn't metered separately for each unit and the garbage fee is lumped in on the same invoice. Anyone have a good solution or example of what they might be doing to offload this cost and help their tenants realize they should turn the faucet off occasionally? Thank you in advance!