Sahih Muslim 740
صحيح مسلم#740SahihJubair b. Mut'im reported:The people contended amongst themselves in the presence of the Messenger of Allah (ﷺ) with regard to bathing. Some of them said: We wash our heads like this and this. Upon this the Messenger (ﷺ) said: As for me I pour three handfuls of water upon my head
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 3:62