Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.002A.
Section : Water from the well of Zamzam.
‘Ali narrated that the Messenger of Allah, upon whom be peace, called for a bucket that contained water from the well of Zamzam. He drank from the bucket, then made ablution (with its water). This hadith is related by Ahmad.