Most people have to pay rates on their homes. Land & Property Services is responsible for collecting this money and can take legal action against you if you don't pay. If you're on a low income you may be entitled to housing benefit or rate relief to help you pay the rates on your home.
You may be able to get a loan to help with your mortgage payments while you are in prison. But, this depends on what benefits you were claiming before you went in and on how long you'll be in prison for. Someone who was living with you may be able to claim help to pay the mortgage if you cannot.