Question:

If a person performs wudu with a can of water and there is water remaining in that can, is he permitted to perform istinja (removal of filth) with the remaining water? Can wudu be performed with the remaining water and is it acceptable for him to throw away the remaining water?

Answer:

Throwing away the water is considered a waste therefore Shariah rules it to be totally unlawful, and to use it for wudu is perfectly fine. However, it will be impermissible to use ther remaining water for wudu, if used water has fallen into it,  to  the  extent  that  it  exceeds  the  amount  of  unused water. With regards to Istinja there is no doubt to it being permissible to use, though with the glory and respect of Shariah in view, it is better that it be used for wudu.

It is stated in Durr  al-Mukhtar: One  should  drink  the  remaining  water  of  wudu whilst standing up and facing the Qibla. The left over water is similar (in virtue) to the water of Zamzam

It is stated in Tirmizi that Hazrat Ali drank the left over water of wudu whilst he was standing and then announced; “I wanted to  let  you  know  of the  way,  in  which the  Holy Prophet ﷺ performed wudu”.

It is stated in Radd al-Mukhtar that the water of Zamzam is a cure for illnesses and so is the left over water of wudu. Allama Abdul Ghani Nablusi states: “Whenever I am ill, I make the intention to drink the left over water of wudu, and by simply making the intention, I am cured from the illness. By having faith in the truthful words of the honest Prophet Muhammad ﷺ I have adapted this way of gaining remedy from any illness”.

And Allah ﷻ knows the best

Imam Ahmad Rida Khan رحمة الله تعالى عليه

Translation by Dr Musharraf Hussain Al-Azhari Translator of Majestic Quran, www.majesticquran.co.uk