It was narrated that Humaid bin ‘Abdur-Rahman said: “I met a man who accompanied the Prophet صلی اللہ علیہ وآلہ وسلم as Abu Hurairah (may Allah be pleased with him), accompanied him for four years. He said: ‘The Messenger of Allah صلی اللہ علیہ وآلہ وسلم forbade any one of us to comb his hair each day, or to urinate in the place where he performs Ghusl, or for a man to perform Ghusl using the leftover water of a woman, or a woman to perform Ghusl using the leftover water of a man — they should scoop it out together.” (Sahih)