This article claims that both chlorine, and chloramine, which are added to many municipal water supplies to kill harmful bacteria, can also harm the good bacteria in soil, necessary for a healthy garden.
It stands to reason that water that’s been treated to kill off bacteria in our drinking water might also kill off the good bacteria in our soil, making it harder and harder to maintain healthy soil.
If it’s chlorine, consider adding a water barrel or two to your garden area that you can fill with municipal water. Let it sit and the chlorine can dissipate before you use it to water.
I'm willing to accept, for the moment, that this may well be true of chloramine, which apparently does not dissipate on its own.
But my understanding of chlorinated water, is that the chlorine will evaporate from the water pretty quickly--the only reason a "few hours" is necessary, is due to the large volume of water... but that chlorine in water droplets--such as in a shower, or in a typical garden watering--will dissipate practically instantaneously.
And even if not all the chlorine dissipates before hitting the ground, I would expect it to dissipate pretty quickly, perhaps having a harmful effect on the "good bacteria" present on leaves, and the top layer of soil. (And I suspect most of this bacteria would be killed by direct sunlight anyway).
Is this article's claim that chlorinated water is harmful for household gardens accurate?