Musannaf Ibn Abi Shayba 1:336

Waki’ narrated to us, he said: Yahya bin Muslim Abu al-Dahhak al-Hamdani narrated to me, from his mother, from her freed slave ‘Awf bin Malik al-Jabiri, from ‘Ali, that he was asked about the leftover water of a cat. He said: "There is no harm in it."