Can I charge for Utilities?

No. Sitters are normally expected to pay their own phone bills, food etc. If it is a long-term ( over 3 months if you are in fulltime Christian work otherwise over 6 months) house sit and there are no animals to be looked after then naturally you can reach an agreement about utility bills. However if there are animals to be looked after we do not allow the charging of utilities
The payment to the sitter is the use of your house and the payment to the owner is having a reliable Christian looking after your home and pets free of charge.