All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
If Zamzam water is transported outside of Makkah, it remains blessed as it is, and what some people say that if it is transported outside of Makkah, its virtue is removed, is not correct.
Shaykh Ibn ‘Uthaymeen said: “Zamzam water is beneficial whether it is inside Makkah or outside it; the general meaning of the Hadeeth in which the Prophet said: ''Zamzam water is for whatever purpose it is drunk for”; applies whether it is drunk in Makkah or outside Makkah, and some scholars of the Salaf (righteous predecessors) used to fill containers of Zamzam water and take them to their countries.”
As regards whether or not Zamzam water expires, then water in general does not have an expiration date after which it becomes expired. Water may change after being kept for a long period of time, or due to something that has fallen into it, in which case, it becomes permissible to discard it if one fears to be harmed by drinking it. Ad-Daaraqutni and others reported that a black man fell into the Zamzam well and died, so Ibn ‘Abbaas ordered that he be taken out and then he ordered that the water be pulled out of the well.
So, it might be that Zamzam water may change due to stagnation for a long time as it is water in any case and we have not come across Islamic evidence that suggests that it does not change.
The fact that Zamzam water is blessed does not mean that it does not change; indeed, Allaah described rain as being ‘blessed water’, while this water can change after a long period of time.
For more benefit on the excellence of Zamzam water in general, please refer to Fatwa 87528.
Allaah Knows best.