Musnad Ahmad 31:817

Ya'qub narrated to us, my father narrated to us, from al-Walid ibn Kathir, he said: Abdullah ibn Abi Salamah narrated to me, that Ubaydullah ibn Abd al-Rahman ibn Rafi' narrated to him, that he heard Abu Sa'id al-Khudri narrating that it was said to the Messenger of Allah, may Allah bless him and grant him peace: "O Messenger of Allah, shall we perform ablution from Bi'r Bada'ah, and it is a well into which menstrual rags, the flesh of dogs, and filth are thrown?" The Messenger of Allah, may Allah bless him and grant him peace, said: "Indeed, water is purifying; nothing makes it impure."