It is my understanding that the ship leaves port loaded with water (city water). This usually lasts about 2 days before they have to take the salt water and filter it to make it into drinking water. So if you do not like city water then you need to have a supply to last for at least the first couple days. I do not like the city water where I live but I have not tasted Port Canaveral water. My cruise is only 3 days so I figured if I had to take water for 2 days, then I might as well take it for 3 days. If anyone knows about the taste of the water in port canaveral, I'd be interested in knowing.