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Chlorine In Your Water: Does It Harm Plants?

If you are living in a major metropolitan area, and receive water from a water company, chances are either chlorine or chloramine is added to the water as a disinfectant. This is actually great news because the chlorine or chloramine kills disease-causing germs like salmonella and norovirus. However, when I was shelling out money for yet another load of worm castings for my garden (worm castings contain a highly active biological mixture of bacteria) it dawned on me that I was adding bacteria to my soil and then watering it in with chlorinated water formulated to kill bacteria. Is this a sustainable practice?

What is Chlorine?

Chlorine is one of the top 10 manufactured chemicals in the United States. It is produced commercially by electrolysis of sodium chloride brine and used as a disinfectant and found in many household cleaning products. It is the basis for most common bleaches.

Chloramine is a combination of chlorine and ammonia. Many water agencies refer to chloramine as monochloramine. According to the world health organization monochloramine is less effective than chlorine for the inactivation of E. Coli and rotaviruses.

According to the U.S. Environmental Protection Agency (EPA), chlorine levels of four parts per million or below in drinking water—whether from a private well or municipal reservoir—are acceptable from a human health standpoint.

How does Chlorine impact my plants?

The Centers for Disease Control and Prevention tells us plants are not harmed by water treated with chlorine. Most of us have been watering our plants with chlorinated water for years and they survive.

How does Chlorine impact the soil?

Chlorine kills some of the microbes in your soil. Making worm tea with chlorinated water defeats the purpose of worm tea. Colorado’s state extension service tells us chlorinated drinking water may kill a number of microorganisms in soil or a compost pile. However, their reproduction rate is so rapid that populations rebound in a short time. In one study, researchers continuously applied highly chlorinated water to soil for 126 days. Two days after they stopped, the soil microorganism populations reached pre-treatment levels at all depths of soil.

I want my plants to thrive not just survive.

There are a few reasons why your garden looks better after a rain. One of these reasons is your plants are receiving non-chlorinated water. I noticed that most indoor agricultural growing facilities using city water run the water through reverse osmosis units to remove chlorine from their water. The carbon filters remove the chlorine. I would also guess anyone making beer or bread/pizza (yeast in water) would want to be sure to eliminate chlorine from their water as well.

The next time you water your garden is a good time to think about the chemicals in your water. You may not be hurting your plants with city water, but most of us want beautiful thriving gardens. We all know the value of rain water for conservation, but considering you are getting water without chlorine is another excellent reason to consider installing one this fall. I will also be looking into a reverse osmosis system for my house and landscape as well as other ways to eliminate chlorine and report back here. If you enjoyed this article please consider subscribing or following me on twitter @H2oTrends.



  • Kishor Thampy ,

    How can chlorine in tap water be removed before watering garden plants?

    • Sprinkler Guy ,

      There are numerous filters that can be attached at the hose bib that use a combination of charcoal and kdf to neutralize the chlorine. Search on Boogie Brew filter and you’ll find several.

    • Rich ,

      12 hours at least in the sun will evaporate most of the chlorine gas.

  • Rich ,

    Good article ty

  • Nola ,

    We have an old pool which has rain water at low level, probably 2 feet water left… a construction crew is throwing debris in it & now they want to add shock or bleach to it. Then they are going to drain it onto our back hill/old lawn. Won’t this hurt mother earth??? Thank you!

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