In addition to the use of the onboard distilling plants, ships also take on fresh water in port, which is filtered, sampled, etc. It is perfectly safe to drink. In fact it is held to higher safety standards than most tap water or bottled water. I've been drinking ship's water for years - in fact I used to "make" it while in the Navy. People get hung up on perceptions and think a bottle of water just has to be better for them. Fact is, most of it comes directly from some municipal water supply. I recently read an article which referred to bottled water as the "pet rock" of this current era.