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?

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    don't know about household gardens, but I do know it can kill aquarium plants and fish (and the bacterial colonies in the filtration system) rapidly. After introducing chlorinated water into an aquarium within hours a good part of your system will have died. Have sadly experienced that myself. – jwenting Sep 5 '13 at 11:26
  • @jwenting: That's a good point... I had forgotten about my relevant experience with aquariums as a child, too... and letting the water sit overnight before adding it, etc... But this is still an example of a large mass of water, rather than a thin mist and thinly-spread layer of ground water, making it still quite distinct from a gardening scenario, I think. – Flimzy Sep 5 '13 at 16:15
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    google.com/search?q=chlorinated+water+gardening returns Planttalk Colorado - Impact of Watering Lawns and gardens with Chlorinated Water as the first result: it says, "no". It's a .edu site so it may be reliable. It backs its assertions by saying "Researchers have found" but it doesn't cite the studies. – ChrisW Sep 6 '13 at 8:00
  • I asked a soil microbiologist about this, and she told me that she always uses reverse-osmosis water for her experiments. However, she was not aware of any studies that explicitly addressed this topic. – adam.r Nov 23 '13 at 2:02

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