and this dung comes from animals whose meat may be eaten and those whose meat may not, and sometimes flesh is found in it: does the water become impure or not?

He answered:

Praise be to Allah. If the dung comes from animals whose meat may be eaten, it is pure according to the majority of scholars, including Mālik and Ahmad ibn Hanbal. Numerous proofs from Islamic revelation establish this, as has been discussed at length elsewhere, where more than ten arguments were presented.

As for water known for certain to have been altered by impurity, it becomes impure. If there is doubt as to whether the dung comes from animals whose meat may be eaten or from those whose meat may not, there are two views in the school of Ahmad and among other scholars. And Allah knows best.

He—may Allah have mercy on him—was asked:

About running water containing dung: is it permissible to perform ablution with it?

He answered:

Praise be to Allah. If it is not known for certain that the dung in it is impure, the water may be pure or impure. It is therefore permissible to perform ablution with it according to one of the two positions transmitted in the school of Ahmad and among other scholars.