adding laundry room to a 3 family in Providence

Hello BP!

I have a 3 family in a nice area close to Brown University in Providence RI. Most rentals include laundry in there units or coin operated in basement, and as of now I have not done anything in regards to laundry and my current tenants aren't pleased. I currently am renting out the 3rd floor and one of the big questions is if I have a laundry. 

I would like to use my utility room in the basement to add 2 sets of coin operated machines , but my issue is that where am I going to get the hot water from? All utilities are separate for the tenants except water. The only thing I have is the separate common electric that I am responsible for. If I add the machines to one of the units water tank than I would have to pay for that units gas bill. Or do I have to add a hot water tank just for the laundry? Not sure what most people do in this situation..

Or I can just add the hookups for each unit and run the electric from my common area panel and run the hot water right from the units hot water tank. And I can charge them an extra $50 for the electric and water usage? would this be my better option.

For the 1st floor I might just add the hookup  in the unit, because I have easy access to the basement and the unit has space for a stackable unit.