In have sailed 6 times on X, and 4 times on RCCL. On all the ships the water is replaced in the morning and evening. The tap water is safe to drink, but not very cold. I use the water in the pitcher because I hate drinking tepid water. At bedtime I fill my glass with ice and let it melt while I sleep, so that when I get up in the middle of the night I have cold water handy.
At other times I use the cold water in the pitcher to brush my teeth, take meds, rehydrate and sometimes fill a water bottle to take on an excursion. That's really the only time you will need bottled water.
I'm sure you will have a great Celebrity cruise!
1/02 Explorer E. Carib. 1/03 Explorer W. Carib. 8/03 Summit Alaska
2/04 Adventure S. Carib. 2/05 Galaxy Panama Canal
6/06 Jewel Brit. Isles/Nor. Fjords 1/07 Mercury Mex. Riv.
1/08 Mercury Aust/NZ 1/09 Galaxy S. Carib. 6/09 Summit Classsical Med.
1/11 Summit S. Carib.