Sayyidah Maymunah bint Sa'd (may Allah be pleased with her) narrates that she said: "O Messenger of Allah! Tell us the ruling on the ritual bath for janabah." The Prophet (peace and blessings be upon him) said: "Wet the roots of the hair and cleanse the skin. The likeness of those who do not bathe properly is like that of a tree which water reaches, yet neither does its leaf sprout nor is its root watered. Fear Allah Almighty and bathe properly, for it is a trust that has been placed upon you, and a hidden matter that has been entrusted to you." I said: "O Messenger of Allah! How much water will suffice for the head?" He said: "Pouring three times with both hands joined together."
Al-Tabarani recorded it in al-Mu'jam al-Kabir through Uthman bin Abd al-Rahman, from Abd al-Hamid, and I have not seen anyone who has given biographical details of these two.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1474