Where do trains store their water for use in the bathrooms?

Question

Another strange conversation - Do the big virgin trains store their water in tanks in each carriage, or is it a central storage somewhere? Also, when they empty their waste, where does it go? On the track or in a storage tank? Any help?

Answer 1

Each coach has both Water and Waste Tanks for each toilet.

Every train built since the class 159s (1992) has waste storage tanks, older trains (ie not Virgin's) still dump on the track.