Does Zakāt become obligatory on money saved for the purpose of buying a house for the family, in US dollars, then converted to Moroccan Dirhams, knowing that parts of it have completed a Hawl (lunar year) while other parts have not? And if Zakāt is paid, does it then become obligatory on the remaining money when a Hawl passes over it? And what is the Niṣāb in Morocco?

Zakat (definition) is not obligatory on wealth unless it reaches the nisab (definition) (minimum threshold) and a full year (hawl) has passed on it. Therefore, zakat is obligatory every year on savings deposited in a bank for purchasing a house or for other purposes, provided it reaches the nisab. As for money added to it or saved from salary, its zakat becomes obligatory after a full year has passed on it. Its zakat can be paid along with the initial wealth, or a separate hawl can be designated for it. It is not a condition for this added money to reach the nisab independently, as it is considered to have reached the nisab by virtue of the initial nisab.