The advent of systemic municipal chlorination of drinking water is considered one of the greatest public health achievements of the 20th century, drastically reducing the spread of waterborne diseases such as cholera and typhoid, and ushering in an era of cleaner, safer tap water. While the addition of chlorine in tap water is responsible for the dramatic reduction in harmful bacteria and viral contamination over the years, more recent studies have demonstrated the more hazardous effects of chlorine in water, such as disinfection byproducts, e.g., chloroform and other trihalomethanes, suggested to be carcinogenic to humans.
While this implies the benefits to treating the presence of chlorine in tap water for people – at least once it enters the home water supply – questions remain on the effects of chlorinated water on non-human life in the home, e.g., your plants and pets.
Plants and Chlorine
When it comes to chlorinated water, plants can be remarkably resilient. Most municipally-treated water contains under 1 ppm of chlorine; because the CDC (Center for Disease Control) recommends a maximum of 4 ppm on chlorine in tap water, it can occasionally be found in concentrations from 1 ppm to 4 ppm. Compared to these chlorine levels, studies have shown that potted or ornamental plants can safely utilize water with as much as 150 ppm (parts per million) of chlorine!
The danger of chlorinated water to plant life comes from the threat to the surrounding microbial biome. Soil contains a host of microorganisms that are essential to the nutrition and growth of plants. Chlorinated water can kill off the upper layers of microbial life in the soil, potentially affecting the plants living in that soil. Plants with deeper roots may be more protected against this possible hazard, though, as chlorine does not penetrate soil easily, and would require a water concentration of 65 ppm or greater to kill microorganisms at six inches below the soil surface.
Aquatic plants are more susceptible to chlorine in the water, as aquatic organisms generally have a much lower tolerance for chlorine, and aquatic organisms lack the buffering effect that physical soil offers. This means that chlorine is a much greater concern for pond life and hydroponic gardens.
Pets and Chlorine
The effects of chlorine on pets depends on whether the chlorinated water is being used for bathing or drinking. Generally, pets can drink chlorinated tap water with little to no ill effects. If you have a chlorinated swimming pool, pets drinking from the pool water can experience some minor gastrointestinal irritation, which can be compounded by any additional chemicals or microorganisms present in the water. Recently shocked pool water – that is, water that contains a much higher level of chlorine in order to quickly raise the level of free chlorine in the water and destroy any microbial life or algae – can make pets very sick upon ingestion. If you have a swimming pool, the best method to keep your pets safe is to make sure they only drink from clean water in their water dish.
Like humans, pets can also be affected by the presence of chlorine in their bath water. A dog or cat’s skin can be sensitive to harsh chemicals, so extended exposure to chlorinated water can irritate their skin, leading to dryness or itchiness. The chlorine in the water can also strip out any natural oils in their hair or fur, drying out your pet’s coat and making it duller and more brittle. This can lead to increased scratching behaviors, potentially causing hair loss or skin infections. And any chlorinated water can also irritate your pet’s eyes if they are splashed with it.
Of course, the degree of this irritation correlates to the level of chlorine in the water. A dog swimming in a chlorinated swimming pool will experience much more skin irritation than a dog washed with tap water. And chlorinated pool water may additionally irritate a pet’s lungs, through the chlorine gas released by pools.
Multipure’s Aquagrow As a Solution
An easy method to ensure the water you use outdoors is free from chlorine for your plants, pets, and aquatic life is to connect a Multipure Aquagrow to your garden hose. Simply attach it inline between your hose and your external water spigot, and your outflow water will be treated for 85% or more of free chlorine. The result is water that is healthier for your soil, your pond, your pets’ drinking water, and for washing your pets. It’s a simple and effective solution to better water for your yard, garden, and pets.
- “Chlorine, Chloramine and Plants – Everything You Need to Know.” Garden Myths. Last accessed June 30, 2021. https://www.gardenmyths.com/chlorine-chloramine-plants/
- “The Effects of a Chlorine Pool on Dogs.” Teddy Bear Pools. February 24, 2015. https://teddybearpools.com/the-effects-of-a-chlorine-pool-on-dogs/
- “Disinfection By-Products.” Centers for Disease Control and Prevention. Last accessed July 1, 2021. https://www.cdc.gov/safewater/chlorination-byproducts.html
- “History of Drinking Water Treatment.” Centers for Disease Control and Prevention. November 26, 2012. https://www.cdc.gov/healthywater/drinking/history.html
- Huntingford, Janice. “Is Chlorine Bad for My Dog’s Skin?” Pet Wellbeing. August 7, 2019. https://blog.petwellbeing.com/is-chlorine-bad-for-my-dogs-skin
- Spengler, Teo. “Will Chlorine in Garden Water Hurt Plants, Trees & Grass?” eHow. Last accessed June 30, 2021. https://www.ehow.com/way_5729155_chlorine-water-hurt-plants-trees_.html
- Vogelsang, Jessica. “Chlorine in Pools: Is It Safe for Pets?” PetMD. June 30, 2021. https://www.petmd.com/dog/seasonal/chlorine-pools-it-safe-pets