I heard the Messenger of Allah ﷺ say, "The water of Zamzam is for whatever purpose it is drunk."
سمعت رسول الله ﷺ يقول: ماء زمزم لما شرب له.
No references are available.
Ibn Majah (3062), Ahmad (14849), and Bayhaqi (5/148) all narrated it from the hadith of Abdullah bin Muammal, that he heard Abu Zubayr say, I heard Jabir bin Abdullah, and he mentioned it. Its isnad is hasan because of Abdullah bin Muammal, for there is disagreement about him, except that he has been corroborated. See its detailed sourcing in the book on Hajj.