ANSWER:

You should say it before making wudu, in your heart, no need to come out of the washroom for this. 

My question is that when we go to the washroom for answering the call of nature and also we have to do Wudu should we say BISMILLAH before entering once or after answering the call of nature we have to come out and then say BISMILLAH again and say the dua of entering the bathroom?

Ablution (Wudhu) | May 26, 2018 2:34 am
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Can someone use flowing water that all every body pass trough it even animals always drink it can we use it to purified our self (2) can we use it for ablution. Please back it up by Quran or hadith
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Is it compulsory to wrap a cloth while doing ghusl for doing wudu.? First we should wrap a cloth and then do wudu and thereafter start pouring the water for ghusl.