Question Summary:
How do I distinguish between urine and water when wetting the bed?

Question Detail:

 
I am a student.I'm boreded at my relatives place for studies.I  sometimes have a bed wetting issue.My questions are as follows
*What  should i do if i cannot distinguish between wether its water or urine.
*If i identify it to be urine and see patches on my cloths but not on the bed sheet.Is it permissible for me to use the bed sheet without washing it.

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
The solution to your query is simple; when waking up from your sleep, if you sense a smell akin to urine or any other foul scent, or you see any distinctive signs of urine such as a yellowish color, then that will be urine and it will be necessary to change the bedsheets, clothes, and purify the body from the filth.^[1]
If there were no traces of urine or any foul smell on your bedsheets, and the urine had not permeated or seeped into the bedsheets, then it will only be necessary to purify the clothes and not the bedsheets.
And Allah Ta’āla Knows Best
AbdulMannan Nizami
Student Darul Iftaa
Chicago, IL, USA
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net