Musnad Ahmad 32:165

Yahya ibn Sa'id narrated to us, from Shu'bah, and Ibn Ja'far narrated to us, Shu'bah narrated to us, from 'Abdullah ibn 'Abdullah ibn Jabr, who said: I heard Anas ibn Malik say: "The Prophet, may Allah bless him and grant him peace, and a woman from his wives would perform ghusl (ritual bath) from a single vessel. He would perform ghusl with five makkuks (a measure of volume), and he would perform wudu (ablution) with one makkuk."