Musnad Abu Ya'la al-Mawsili 148:59

Abu Khaythama narrated to us, Abd al-Rahman narrated to us, Sufyan narrated to us, from Abdullah ibn Abdullah ibn Jabr, who said: I heard Anas saying: The Messenger of Allah (may Allah bless him and grant him peace) and some of his wives used to perform ghusl (ritual bathing) from a single vessel.