Assalaamu alaykkum, While consuming milk we add water and drink it. Is that allowed or is it haraam? I also heard someone saying that mixing water with milk and drinking is good for the knees. So i kindly request you to state whether mixing water in milk is haraam or halal? And under what circumstances should it be done?

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

It is permissible to mix milk with some water when drinking it, indeed, it is confirmed that the Prophet was given milk that was mixed with water and he drank from it. [Al-Bukhari and Muslim]

As regards whether mixing milk with water is good for the knees, then we are not aware of this and you may consult the specialists in the field about this and about the cases in which this can be done.

Allaah Knows best.