Some passengers mistakenly believe that there is salt in the ship’s tap water which causes their ankles to swell, and try to avoid that by bringing their own bottled water aboard, especially if they don’t have a beverage package.
in truth, this is a mistaken belief. The ships tap water does not contain salt. However, some of the food is heavily salted. For those who do not add salt to their food at home, they may find that the addition of the salt in the food they consume on board can cause ankle swelling, in combination with some possible mild dehydration. The solution is to drink more water. Tap or bottled, it won’t matter.