Sunan an-Nasa'i 249
سنن النسائي#249Sahihأَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ يَزِيدَ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، رضى الله عنها أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُشَرِّبُ رَأْسَهُ ثُمَّ يَحْثِي عَلَيْهِ ثَلاَثًا .
It was narrated from 'Aishah that the Messenger of Allah (ﷺ) used to soak his head, then he would pour water over it three times
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 1:250