Why no buy a water filter jug or fit a filter system to your main water feed, surely normal water would not affect every day drinking, but in the case of adding antibiotics etc, then use filtered water so it does not nutralise them
Leaving the water overnight lets the chlorine evaporate, as far as fresh, the waters been in the pipe system for days before it gets to you
There is an ultraviolet system that purifies your water, not sure about chlorine though
Get a test kit from your pet shop and test your water, used for tropical fish to get correct water balance, ph levels, alkaline levels, acidic levels etc