Is zakat obligatory on the orphans' money (money held in trust for a minor) and on the heirs' money from which monthly withdrawals are made to cover obligations and which they receive intermittently throughout the year? What is its amount and when is it due? Is zakat obligatory on the house their father left them in the countryside?

Zakat is obligatory on inherited money when the heir's share reaches the nisab (minimum threshold) of gold (85 grams) or silver (595 grams), and a full lunar year (hawl) has passed on it. The amount of zakat is a quarter of a tenth (2.5%). However, if the amount falls below the nisab during the year, there is no zakat on it until it reaches the nisab again and a full year passes on it. There is no zakat on an inherited house.