كتاب الحيض
3  
The Book of Menstruation
(10)
Chapter: The amount of water with which it is recommended to perform ghusl in the case of janabah; a man and woman washing from a single vessel; one of them washing with the left-over water of the other
(10)
باب الْقَدْرِ الْمُسْتَحَبِّ مِنَ الْمَاءِ فِي غُسْلِ الْجَنَابَةِ وَغُسْلِ الرَّجُلِ وَالْمَرْأَةِ فِي إِنَاءٍ وَاحِدٍ فِي حَالَةٍ وَاحِدَةٍ وَغُسْلِ أَحَدِهِمَا بِفَضْلِ الآخَرِ
Sahih Muslim 325 b

Anas said:

The Apostle of Allah (ﷺ) performed ablution with one Mudd and took bath with a Sa' up to five Mudds.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا وَكِيعٌ، عَنْ مِسْعَرٍ، عَنِ ابْنِ جَبْرٍ، عَنْ أَنَسِ، قَالَ كَانَ النَّبِيُّ صلى الله عليه وسلم يَتَوَضَّأُ بِالْمُدِّ وَيَغْتَسِلُ بِالصَّاعِ إِلَى خَمْسَةِ أَمْدَادٍ ‏.‏
Reference : Sahih Muslim 325b
In-book reference : Book 3, Hadith 59
USC-MSA web (English) reference : Book 3, Hadith 635
  (deprecated numbering scheme)