Over the years, on various boats I have been on, the water systems were at best somewhat iffy...
Water tanks tended to become contaminated, impart tastes or become breeding grounds for all sorts of evil flora and fauna. If that was not enough, electric pumps tended to fail when/where they'd be the most problematic and the hoses connecting the system together tended to grow purple stuff...
Purple stuff is yucky!
On the other hand, avoiding all of that is pretty simple as all you have to do is get rid of it all and go simple... On "So It Goes" (and the LM"S before) we use a simple system based on plastic jerry cans. Three five-gallon jerry cans fit under the galley sink and a short hose from the galley pump (a Whale manual) simply goes into the neck of the current jerry can in use.
The advantages of such a system is it keeps you up-close-and-personal with water consumption and quality. A bonus is if you do have a contamination problem it is unlikely to be in more than one water container. Also, since the amount of water you can carry depends simply on the number of containers you carry it is easy to adapt for a long cruise by simply adding more jerry cans or other suitable containers. On "So It Goes" we routinely carry six five-gallon jerry cans and for longer voyages we have a number of three-gallon containers as well as a couple of collapsible five-gallon containers. An added bonus to this system is that we can stow the water around the boat to balance weight and trim.
Speaking of contamination... One way we avoid taking on water of questionable quality is we simply do not trust water anywhere and refilter it before it becomes part of the ship's supply. For instance, the water you get here in St Croix from the marina comes out of the hose looking OK but since it is coming from old iron pipes there is a very high rust component to the mix. If you let a jerry can sit for a couple of hours the bottom six inches of the water will be a deep orangey/red color. While I know a little iron is good for you, this is not the sort of water I want making my morning coffee! Of course, you can get along quite well with orange colored water but other places, while not orange, can contain all sorts of nasty bugs and parasites that are seriously scary...
