Is this illegal/unethical?

[Joseph Weisenbloom]

I am currently closing on a duplex and I plan to live in one side and and rent the other out. The electric and gas are separately metered and are easy to have these expenses paid by the other renter. The water on the other hand is under one meter which makes it harder to delegate expense. It is typical in my area for the tenant to pay utilities separate from rent

My question is it illegal/unethical to have the water bill put under the tenants name and paid by them even though I will be using the water as well? Has anyone ever done this before?

I guess the alternative would be to increase rent to include water or charge some type of monthly water fee?

Thoughts?