The Book of Purification
1/158. Chapter:
Mention Of How Much Water Is Sufficient For The Junub Person To Pour Over His Head
Sunan an-Nasai
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا أَبُو الأَحْوَصِ، عَنْ أَبِي إِسْحَاقَ، عَنْ سُلَيْمَانَ بْنِ صُرَدٍ، عَنْ جُبَيْرِ بْنِ مُطْعِمٍ، قَالَ تَمَارَوْا فِي الْغُسْلِ عِنْدَ رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ بَعْضُ الْقَوْمِ إِنِّي لأَغْسِلُ كَذَا وَكَذَا . فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَمَّا أَنَا فَأُفِيضُ عَلَى رَأْسِي ثَلاَثَ أَكُفٍّ " .
It was narrated that Jubair bin Mut'im said: "They argued about Ghusl in the presence of the messenger of Allah (ﷺ). One of the people said: 'I perform Ghusl in such-and-such a manner.' The Messenger of Allah (ﷺ) said: 'As for me, I pour three handfuls of water over my head.'"
Reference : Sunan an-Nasa'i 250In-book reference : Book 1, Hadith 251English translation : Vol. 1, Book 1, Hadith 251