It was narrated from Ibn 'Abbas that:
One of the wives of the Prophet took a bath to cleanse herself from sexual impurity, then the Prophet performed ablution and had a bath with the water left over from her ablution." (RU)
English reference (RU): Vol. 1, Book 1, Hadith 371 (RU)
Arabic reference (RU): Book 1, Hadith 401 (RU)