The Shaykh (Al-Mufid), may Allah سبحانه وتعالى support him, narrated to me from Abu al-Qasim Ja'far ibn Muhammad, from his father, from Sa'd ibn Abdullah, from Abu Ja'far Ahmad ibn Muhammad, from Uthman ibn Isa, from Sama‘ah ibn Mehran, from Abu Basir, from Abu Abdullah عليه السلام, who said: Imam عليه السلام said: "There is no harm in the leftover water (su’r) of a cat; it can be used for Wudu' (ablution) and drinking. However, the leftover water of a dog should not be drunk, unless it is from a large pool that people draw water from."