كَانَ النَّبِيُّ صلى الله عليه وسلم إِذَا تَبَرَّزَ لِحَاجَتِهِ أَتَيْتُهُ بِمَاءٍ فَيَغْسِلُ بِهِ.
Anas ibn Malik reported: When the Prophet ﷺ went out to relieve himself, I would bring him water and he would wash himself with it.
also in Sahih al-Bukhari 150, Sahih al-Bukhari 151, Sahih al-Bukhari 500