Hajj & Umrah

Packing Zam Zam in one's bag when returning from umrah or hajj

Q: When coming back from Hajj/Umrah, Saudi has a rule that each pilgrim may only bring with him 5 litres of zamzam, packed in a special box. People say that the reason for the rule is that they want to avoid water packed in normal bags from spilling on the luggage bands. If a person secretly packs extra zamzam in his normal bags, will he be sinful for breaking the 5 litre rule even if he packs it in a way that he is sure there is no leakage?