Raising Rent & Making tenants pay utilities

[Noah Masa]

Hi, 

looking for some help/advice on an opportunity I have come across. Multi-unit, 2bed/2bath and 1 bed/1bath. Current tenants are on a month/month lease, and both pay less than half of market average for rent. Currently pay 750 Current owners pays for garbage and water, rest of utilities go to tenant. 
1.) can I assume I can raise rent by more than half of current price if I were to purchase? 

2.) is it possible to transfer the responsibility of water and garbage to the tenants?