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." (TH)
English reference (TH): Vol. 1, Book 1, Hadith 371 (TH)
Arabic reference (TH): Book 1, Hadith 401 (TH)