Current tenant is not paying utilities...

[Justin B.]

I am set to take over a duplex and the current tenant is not paying any utilities right now for a 3 bedroom lower unit. She pays $600 a month which I believe is fair if I didn't have to pay their utilities.  I want to make sure the tenants take over the utilities which for her is running 100-125 a month avg, how do you broach the subject, especially in the beginning of winter, paying utilities is one thing, replacing a tenant is another...