Last fall in Hawaii I was drinking 4-5 liters per day (plus an additional 1-2 liters of water content from the fruits and veggies I was eating)
I felt great, had regular BMs, slept very well, had softer skin, and no bags under my eyes...
It was a cold winter in my part of CA so I stopped drinking as much but I'm trying to start again because I felt so much better!
Although it could be difficult with the reduced bladder size from HRT...