Sahih al-Bukhari 255
صحيح البخاري#255SahihNarrated Jabir bin `Abdullah:The Prophet (ﷺ) used to pour water three times on his 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 al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 5:8