Shaykh al-Islam Ibn Taymiyyah stated: “The baseline regarding animal droppings is that they are pure, except for those explicitly exempted …” End quote.

The residual food or drink of any animal whose meat is lawful to eat is pure.

Likewise, the cat’s residual water is pure, in view of the ḥadīth of Abū Qatādah about the cat in which the Prophet said, “It is not impure; it is one of those that move about among you.” Al-Tirmidhī and others related the report and judged it authentic. The cat is compared to household servants who circulate among the family, and because it is difficult to keep it away; thus hardship and inconvenience are removed.

Some scholars have extended the ruling of the cat to anything smaller than it in form—such as birds and the like—so the residual water of such creatures is pure just like that of the cat, since they too roam freely around people.

Everything else whose meat is not lawful to eat—including what was grouped with it—has droppings, urine, and residual water that are all impure.