Must be nice to live in a place where you can drink the water from the tap. I don't happen to live in a place like that. We filter our water before we drink it. The public water system we are on draws from the river bed. When it rains really hard, and the river is at flood stage, the water reeks of extra chlorine. When flood stage water gets into the holding tank of the water system, they go door to door posting notices not to use the water at all. Country-living PITA. Because the amount of chemicals in the water varies with the amount of pollutants in the water on any given day, there is no way I would not use Prime when doing water changes--even on nice sunny summer days.