Our sweet and saltie lives separate in some areas and this is one of them: while in the middle of the very deep, clear waters of Manitowaning Bay, we used our wash down pump to fill our water tanks. There was good potable water at Manitowaning, but we didn’t have a hose long enough to reach to fill our water tanks. So while sailing in the middle of the bay, we poured a bit of bleach (about a tablespoon) into our tanks, ran the wash down pump a while to make certain the hose was clear, then filled our tanks. We mostly use this water for washing dishes and maybe taking the rare shower, but will also use it for making coffee and tea.
I would never have done this prior to an episode we had back many years ago, when our children were very young. We filled our water tanks at a small marina in northern Lake Huron (I will not mention the name). Within hours of using water from the just-filled tank, we began getting sick: first our two children, then the four adults on board. We were violently ill with diarrhea for several hours, rapidly realizing that we had filled our tanks with tainted water (we believe that the hose for potable water had been used to wash down after a pump out). Since then, if we are running low on water and a dependable water supply is not easily accessible, we will take water from deep areas of Lake Superior, Georgian Bay, and select areas of northern Lake Huron. There is no water as sweet as the water dipped out of the cold, deep waters of Lake Superior!