I think areating your water overnight is the easiest/cheapest way to dissipate any chemicals in the water, don't forget most municipalities also add flouride but I'm not sure if it dissipates like chlorine or not. I've given freshly sprouted seedlings straight tap water without any problems. I prefer to areate it but I'm not 100% consistent with it except whenever I fertilize, then I always areate the water with the fertilizer added.

I've read that you should not use water from the hot side of your faucet if you're drawing from an indoor source, apparently the water has other sediments/agents as a result of sitting in the water heater. Independent of this I've also read you should not drink water from the hot side of your faucet, always draw from the cold side and heat your water that way.
Purple Daddy Reviewed by Purple Daddy on . WATER QUESTIONS? Hello, there is a theory that you should let tap water sit out for 24-48 hrs before using it, my question is if you let it sit out covered or sealed (I.E. old plastic milk containers with the cap on) is it doing any good, or does it need to sit uncovered? newbie thanks!;) Rating: 5