Question:

What is the ruling of using sewage water, after treating it and thoroughly purifying it from all kinds of impurities, in customs and acts of worship, in drinking it and in food, in performing ablution and Ghusl (ritual bath) and for all other purifications? It should be noted that this water, as mentioned by government reports, is purer than used water from wells which is almost all consumed?

Fatwa:

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

If it is possible to treat and purify this water from impurities, in regard to its taste, colour and smell, then there is no harm in using it for the purpose of purification. There is no harm also to use it in eating and drinking if it is confirmed that it does not cause any harm. The scholars ruled that a big quantity of water which is changed by an impurity is possible to be purified if the change disappears by itself, or by adding pure water to it, or removing its change by being stable in one place for a very long time, and the like. If the reason of the change disappeared, the water becomes pure, and the ruling will no longer apply if the reason for it has disappeared.

Allah Knows best. 

Fatwa answered by: The Fatwa Center at Islamweb