Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Responding to your question, Dr. Hatem Al-Hajj, Dean of College of Islamic Studies, Mishkah University, states:
1. As for the first question, no, you don’t have to pay Zakah on this apartment.
2. No, you don’t have to pay Zakah as long as you still use it, and it has not become purely merchandise, once you are only keeping it as merchandise, it becomes Zakatable.
3. With regard to your sister, yes, you may give her your Zakah money and all of your relatives as well except your ancestors and descendants whom you are responsible for financing.
4. If you do that for her benefit, you must separate the money from yours and consider it hers, and give it to her in installments. People in your household must know it is your sister’s money. In general, Zakah must be given away once it is due.
5. Yes, you may give your Zakah money before it is due by up to one year.
Almighty Allah knows best.
Editor’s note: This fatwa is from Ask the Scholar’s archive and was originally published at an earlier date.