Is that a trick question? 
If you have water with you, there is no need to go find any.  Personally, and I don't think I'm alone on this, I need water.  Dehydration is not fun.
While it could be some sugary carbonated liquid rather than water carried, I prefer water.  Apparently, others do too.  The type and 'pedigree' of water is always something to question, but having water with you?  Yes.  I also always carry a pocket knife.
I'm a boy scout leader, so being prepared is part of my life.  I carry a one liter playtpus water bottle with me every day to work because the water there tastes bad.  However, most people bring bottled water.  I also like to keep water in my vehicle along with a first aid kit.  It's part of being prepared, self sufficent, as well as a time saver.  Mankind has been doing this for millennia, disposable polyethelyene bottles just make having water with you easier and more convenient.  
Regards,
Malta