I have two 35 gallon polyethylene water tanks
. I fill them strictly with municipal water from the dock
or a hose bib, through a household water filter, adding one tablespoon of bleach to each tank. I drink it and my water has always been clear and fresh.
For some reason, it seems that many marinas
supply well water to their docks, from wells on their premises. There are always people drinking that. If it's clean and I trust it I'll wash my dishes in it, but that's it. I would never drink or cook with such well water. Where there's a well, there's a septic system nearby.