Mishkat al-Masabih #444

Abu Sa'id al-Khudri said that some people asked God’s messenger whether they might perform ablution out of the well of Buda‘a, which was a well into which menstrual cloths, dead dogs and stinking things were thrown, and he replied, “Water is pure and is not defiled by anything.” Ahmad, Tirmidhi, Abu Dawud and Nasa’i transmitted it.