Are there Hadiths discussing when it is sunnah to drink ZamZam?
I haven’t seen such details, besides the fact that Rasulullah (sallallahu’alayhi wasallam) is reported to have drank from Zamzam during his Haj.
(Musnad Ahmad, vol.3 pg.394)
Some ‘Ulama have encouraged a fasting person to make iftar with zamzam (mustahab).
(Fadlu Ma-i Zamzam, pg.132)
However, one should drink zamzam whenever possible, as it is the most blessed water found on earth.
Furthermore, Rasulullah (sallallahu’alayhi wasallam) has said:
‘The water of zam zam is [suitable] for whatever purpose it is drank for.’
(Sunan Ibn Majah, Hadith: 3062 and Musnad Ahmad, vol.3 pg.357)
Therefore, whenever one has a need, one should drink zamzam with the intention of fulfilling that need.
See here for more virtues on Zamzam.
And Allah Ta’ala Knows best,
Answered by: Moulana Muhammad Abasoomar