The Messenger of Allah ﷺ used to bathe with five makkuks of water and perform ablution with one makkuk.
حدثنا بهز حدثنا شعبة حدثنا عبد الله بن عبد الله بن جبر أنه سمع
كان رسول الله ﷺ يغتسل بخمسة مكاكيك ويتوضأ بمكوك
Its isnad is sahih, and it has already appeared at number 13925.