“I once wrote to a person to write to abu al-Hassan al-Rida (a.s.), to ask him about a well in one’s house for Wudu’. If some drops of urine, or blood, or animal dung and so forth fall in it, then how can it be cleansed so one can take Wudu’ with water from such a well for Salah (prayer). He (the Imam) sent the answer with his signature that said, ’Draw a few buckets of water from it and dispose such water away.’”