I'll just come in hear as a regular Seabourn sailor.
I always drink Evian water wherever I am.
On my two cruises in August,both ships did not have Evian but they had Aqua Panna which is in glass bottles and the water was good.
Ships now have a water system that allows you to fill a water bottle around the ship,it is also served at the table when dining and also around the deck from the bars.
I don't like this water or the taste of it.
Many people were fine with it so until you try it and see then don't worry unnecessarily.