The water from the sink is very clear. In fact, it is probabilly purer than the tap water from your sink at home. The CDC inspects potable water treatment and storage extremely rigourously every six months, and has been known to dock inspection points from ships for apparently minor problems such as using the wrong color striping on the potable water pipes. Some people, however, note that the water might taste a little flatter than what you are used to. This may impact water, coffee, and some fruit juices. I personally think the water tastes fine, but if you want to bring a bottle along for when you go ashore, you can do that, too.