DON'T BUY IT! Unless it is to get the bottle to have something to refill. The tap water and the water from the dispensers in the buffet areas is as good if not better than bottled water. As the ship typically generate all the drinking water the ship needs, it is very pure. They use the same equipment many water bottlers use.
On Sapphire Princess the drinkwater smells/tastes very strong on "Chlor" (germicide to desinfect the water).
I find, it was only drinkable with lemon slices.
The free coffe at the buffet was cooked with the same water, so it tastes better.
I mean, our water in our village or the mineralwaters like Adelholzener, Apollinaris, San Pellegrino, Perrier or Selters tastes much better than the drinkwater on the Sapphire Princess.
regensburger- I have never run into that problem. The worst water I have found was on the NCL Dream. But it was not a problem with taste, they had the water temperature set very high and even the cold water was too warm to try to drink from the tap unless you have ice.
Maybe they were having a problem with there purifier system when you were on board that caused do much chlorine taste?