Just a note of clarification on something that is commonly misunderstood.
Chlorine will dissipate (evaporate) into the air from tap water that is left standing in an open container. However, the concentration of chlorine in most municipal water supplies is too low to cause any significant damage to
plants. Pool water with its high concentration of chlorine will definitely damage many
plants.
Fluoride does not dissipate from open containers. Only special filters will remove fluoride from water. However, again, the level of concentration is too low for it to be of much concern. Damaging concentrations of fluoride are more likely to occur with perlite and some fertilizers (superphosphate), than from fluoridated water.
Other minerals found in hard tap water do not evaporate. Special filters can remove these minerals, which are damaging to
plants. You can also use distilled or rainwater instead, if your local tap water is on the hard side.
I care for thousands of
plants in NYC where the water is both fluoridated and chlorinated, but not hard. I use water straight from the tap for all of these
plants with no harmful results.