Abu Dawud Book 1, Hadith Number 28.

Chapter : Urinating in the bath.

Narated By A Man from the Companions : Humayd al-Himyari said: I met a man (Companion of the Prophet) who remained in the company of the Prophet (PBUH) just as AbuHurayrah remained in his company. He then added: The Apostle of Allah (PBUH) forbade that anyone amongst us should comb (his hair) every day or urinate in the place where he takes a bath.