Praise be to Allah.
Those to whom zakaah may be given have been described by Allaah in the verse in which He says (interpretation of the meaning):
“As-Sadaqaat (here it means Zakaah) are only for the Fuqaraa’ (poor), and Al‑Masaakeen (the poor) and those employed to collect (the funds); and to attract the hearts of those who have been inclined (towards Islam); and to free the captives; and for those in debt; and for Allaah’s Cause (i.e. for Mujaahidoon — those fighting in a holy battle), and for the wayfarer (a traveller who is cut off from everything); a duty imposed by Allaah. And Allaah is All-Knower, All-Wise”
The poor person is the one who has no income, or who has an income that is not sufficient.
This varies from one time and place and family to another, but there are some cases which all are agreed are entitled to zakaah, because their income is so low.
The fuqaha’ say: The poor person who is entitled to zakaah is the one who cannot find enough for himself and his family for one year.
If a person receives a monthly salary, then we should look at what his annual income is, and at what he needs for maintenance throughout the year. For example, if what he earns in one year is five thousand but he needs ten thousand to live on, then he is poor or needy because he only has half of what he needs.
See: al-Sharh al-Mumti’ (2/672).
Similarly, if he needs six thousand and his income is only five thousand, then he is entitled to zakaah.
It may be that he has enough for him and his family, but he is in debt and cannot afford to pay it off. So he should be given enough to pay off his debt. Or he may have enough to eat, drink and pay for shelter, but he needs to get married and cannot afford to pay the dowry, so he may be given enough to get married with.
If there is a Muslim who is a new convert and he is in prison, if he is poor or in debt, he may be given zakaah enough to suffice him and his family, and to pay off his debt.
There is nothing wrong with giving him zakaah – even if he is independent of means – if that will attract his heart and strengthen his faith and make him steadfast in Islam, especially if he is prominent among his people and that will result in attracting the hearts of those who are with him. Allaah has given a share of zakaah to those whose hearts are inclined towards Islam.
It is permissible to give charity to pay utility bills that are due, because charity is broad in scope. It may even be given to one who is independent of means, but it is important to pay attention to finding out who is more deserving and in greater need.
It is permissible to pay bills with zakaah if the person cannot afford to pay them, because having bills means that he is a debtor.
And Allaah knows best.