I gave up on soil several years ago, and only grow using aeroponics now, but even back then I did not need to leave my water sit. My water comes from a community well and has no chlorine in it. Other than having moderately high calcium hardness (makes PH control a littler more difficult) my water is pretty good.
Not trying top chace you out, but if you are growing in soil, there are other sections on this forum dedicated to soil growing. This is the hydro section
Most of us started out growing in soil, so we all probably have some experience with soil, but you might get better, or more up to date advice in one of those sections.