The quality of our drinking water is a major determinant of our health and wellbeing. It is important to consider not only the presence of pathogens or contaminants, but also the routine addition of chemicals that may cause us harm. Chlorine is a chemical typically used as a disinfectant in public water supplies as an effective way to reduce the level of pathogenic bacteria in our drinking water. (1)
Unfortunately, this chemical, and other common chemical disinfectants, may have a damaging impact on our bodies’ beneficial bacteria as well.
When chlorine is used as a water treatment, it combines with organic matter to form compounds called trihalomethanes (THMs), also known as disinfectant byproducts. One of the most common THMs formed is chloroform, which is a known carcinogen. (2) Other THMs formed include the di- and trichloramines formed when chloramine is used as a disinfecting agent. (3) These compounds are toxic when consumed, inhaled, or applied to the skin.
Research conducted on the health effects of chlorinated drinking water have demonstrated a variety of toxicity issues. Several studies have found that communities using chlorinated or chloraminated drinking water have an increased risk of bladder, kidney, and rectal cancers. (4, 5, 6) THMs from chemically treated water have been associated with a variety of poor birth outcomes, such as spontaneous abortion, birth defects, and low birth weight. (7) Chlorine and chloramine vapors are associated with greater risk of asthma, and may damage the mucosal lining of the respiratory tract. (8) Free radicals in chlorinated water have been linked to liver malfunction, weakening of the immune system and pre-arteriosclerotic changes in arteries. (9)
While there hasn’t been substantial research on the topic, it’s reasonable to assume that chlorinated water adversely affects beneficial intestinal flora. Chlorine is a powerful antimicrobial agent, and is an effective pesticide against many different strains of bacteria. (10) The compounds in disinfected water may be able to reach the gut not only through our drinking water, but also through daily showers and baths.
A recent post at the Food Renegade blog (11) brought this disturbing theory to light, not only highlighting the harmful effects of chlorinated drinking water, but emphasizing the possibly greater effect that showers and baths could have on our intestinal flora. As we know, there’s a strong connection between asthma, acne, autoimmune conditions and the health of our gut flora. We might speculate that dysbiosis induced or made worse by excess chlorine exposure could contribute to these conditions.
Showering and bathing in chlorinated water may expose us to even more chlorine and its byproducts than drinking this disinfected water.
While our bodies can filter out much of the chlorine from our drinking water, the THMs and other disinfectant byproducts we inhale during showers and baths may be much more harmful, since the chlorine gas we inhale enters directly into our blood stream. (12) Therefore, even if you filter your drinking water, the amount of toxins you are exposed to from your daily shower or bath, through inhalation or skin absorption, may be cause for greater concern.
Research has demonstrated that the cancer risk associated with chlorinated water may actually be due to showering and bathing, rather than drinking the disinfected water. (13, 14) This suggests that many health risks of chlorine may be specifically related to dermal and inhalation exposure. In fact, the chloroform dose from a single, ten minute shower is equal to, and possibly greater than, that from the average two liters of water ingestion on a daily basis. (15, 16)
Therefore, the filtration of your shower and bath water may be even more important than the water you drink.
Chlorine filtration is fairly simple, provided you use some level of technology to remove it from your shower or bath water. There are resources on the Food Renegade blog about where to find chlorine-filtering shower heads and bath filters. (17) This includes the Rainshow’r Shower Filter and the Crystal Ball Bath Dechlorinator, both sold by the Radiant Life Company.
I’d like to point out that chlorine isn’t in everyone’s water supply, but there is another disinfectant that is also of concern. I checked my local water company’s website, and discovered they use chloramine (chlorine + ammonia) to disinfect the water supply. (17) Chloramine exposure may be even more damaging to the lung epithelium than chlorine, and may release ammonia as another toxic byproduct as well.
The filters that remove chlorine don’t necessarily remove chloramine.
Chloramine can be removed for drinking water purposes by a carbon block or activated carbon filter that can be installed on a kitchen faucet. Also, both chlorine and chloramine can be removed for bathing purposes by dissolving Vitamin C in the bath water. One 1000 mg Vitamin C tablet will neutralize chloramine in an average bathtub. (18)
There are no shower filters on the market that completely remove chloramine. (19) There are, however, whole house water filters that remove chlorine, chloramine, and other contaminants. Unfortunately, they’re quite expensive and thus may not be an option for many people.
Vitamin C shower filters may be a good choice for those looking for an inexpensive way to reduce the chloramine (and chlorine) content of their showers. Vitamin C is an effective dechlorination agent, removing up to 99% of chlorine and chloramine, and vitamin C filters are much less expensive than the whole house filter featured above. The disadvantage to using them is they’re not as durable or effective as a whole house filtration system, and you would need a separate filter for each shower outlet in the house.
Other simple methods to reduce exposure to chlorine and chloramine include: taking shorter or less frequent showers, avoiding excessively hot showers (since high heat increases the amount of steam), and shutting the water off while soaping up. These techniques will help decrease your exposure if filtration or dechlorination is not an option.
I recommend you check with your local water supply company to determine what disinfecting agents they use to sanitize your tap water. You can then use that information to make a decision about which shower filter is most appropriate for you and your family. Until we know more about how chlorinated water affects our health, and especially our beneficial gut flora, it seems prudent to keep chlorine and chloramine exposure to a minimum.
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{ 47 comments… read them below or add one }
Thank you for this amazing article, I didn’t know about the vitamin C.
What about people who swim for exercise or sport? They may actually may be an interesting control group to test the effect of chlorine on the body.
Good point Yolanda!
I 2nd this idea -it seems it would be pretty easy to study people who swim on a regular basis?
Excellent observation! When I’m training, I can be in the pool 4-6 hours per day. When I’ve had to swim in chlorinated pools, I frequently get IBS symptoms. Yet, salinated pools, I can swim all day for months on end without experiencing any of those symptoms. Not to mention, my skin doesn’t get dried out either.
FYI, salt pools do use chlorine. The salt system simply reduces the amount of chlorine used 70-90%. The amount of chlorine in a salt pool is still significantly greater than the amount of chlorine in your city water supply.
Also, I’m sure there are studies that have been done on chlorine use and the effects of chlorine on humans. There is probably evidence out there that the amount of risk associated of dying of cancer from chlorinated water supplies are insignificant when compared to the benefits gained. Hence, drinking contaminated water with bacteria and other pathogens is more dangerous than consuming miniscule amounts of chlorine.
To the author, while it is nice to expose us to this information, it is not new. I haven’t done any research on this topic (other than being a civil engineer that designs water systems), however, I am confident that studies have been done on this when it was introduced decades ago. chlorine is better than contaminated water. the risk of serious side effects is insignifacnt compared to the benefits to the people receiving the treated water. (putting a filter on your home though is a good idea). This is the same principle as stating that driving is bad because people die or become paralized. the benefits of driving and the risk of being in an accident outweigh the negative posibilities. While it would be nice if everyone drove a volvo and put on a seat belt, it still wouldn’t remove the risk. everything has a risk associated with it. the issue here is being practical. educating and exposing people is fantastic, but it also needs to be placed in context. It’s not necessary for everyone to drive a volvo, and not everyone will die in a car accident.
Chris, another great article!
I’ve been a victim to the hands of chlorine…in fact bromine treated, as well as chlorine treated water. For years my parents thought the mood swings and personality changes were just ‘angry child syndrome’ until I stopped swimming lessons at school.
Nowadays I have all drinking and washing water filtered and thankfully Manage the symptoms when outside of my own home with (now) herbal remedies.
I’m glad you are sharing the knowledge, I just wanted to say that sometimes the most unexpected of symptoms can result from these chemicals.
One of my mentors would frequently talk about the dangers of chlorine in shower water, but I never really researched the topic.
I appreciate the great article, as well as all the sources you reference. Wishing you all the best, Chris
Interesting article – important things to consider. As a practicing nutritionist, I recall a client I had that was a competitive swimmer. Despite one hour plus of strenuous exercising six days a week, and what seemed like a not-awful diet, she was carrying 40 extra pounds. Because she was not interested in doing extensive lab testing, I could only surmise that her exposure to chlorinated pool water was causing health problems (hypothyroidism as evidenced by chronic fatigue, or perhaps gut dysbiosis or other problems) that could not be resolved by diet alone. She did not want to stop swimming and therefore stopped seeing me. Thanks for this information.
I called my water company about the additives to our water supply. There is chlorine, plus soda ash and flouride. What are your thoughts on flouride consumption/exposure? And do you know of a way to remove it? Also, I have never heard anything about sodium carbonate being problematic to our health, but I would love to hear your thoughts on whether it could pose risks in our drinking or showering water.
Just FYI for anyone out there looking for a chlorine shower filter: We got ours at Home Depot or Lowes for about $30 and it was very easy to install. A filter lasts us about six months and is about $10 to replace. We take a lot of baths, and couldn’t find a filter for the main bath faucet, so we bought a shower head with a hose on it and just use that to fill the bath. It also makes bathing the baby much easier.
Hi Angela I bought the Berkey water filtration that has flouride filters for drinking water.I love my water!!
Fluoride requires a reverse osmosis filter.
Fluoride can also be removed by distillation and activated alumina.
Recently my city began to put flouride in our water. I did a little research and found out that the most economic way of removing flouride is to use a water distiller. I bought one on Amazon and have enjoyed pure distilled water since.
A friend who studies environmental issues raised this concern 5 or so years ago and I totally forgot about it. Thanks for the reminder!!!
Now that I have children, and we rent, is there a filter for the bath spout and not just the shower head? I guess I could get the shower head and run it to fill a bath with hot water so that it’s not too cold.
I love being a parent, but it seems the natural health world is set up for adults without children. Who’s the engineer out there who will make a killing creating a vitamin C bath spigot filter for the kiddies?
There are bath filters, that hang from the faucet, and de-chlorinate the water, as it flows through a filter. Just go on line. One is called the Enviro Splish Splash.
I always appreciate your blog posts, Chris. Thanks.
I was a competitive swimmer from age 7 through college, and I ended up getting Crohn’s disease, though several years after I had stopped swimming. I had read about how chlorine could impact your gut flora (after I got diagnosed), so I often wonder if there’s a possible link. My younger sister was also a competitive swimmer for just as long, and so far she hasn’t developed Crohn’s, and I hope she never does. Obviously there are other factors involved in activating Crohn’s, but as Yolanda mentioned, it would be interesting to see a group study on swimmers and their intestinal flora.
In short, we’re all going to die. This is one of those that, hm, great to know but, am I going to be scared of taking a shower in the morning or giving baths to my children? no, I’ll have to file it under “show me hard evidence first”. Actually I’m erasing what I just read from my memory (concentrating real-hard now). Also, after many years of struggling and sacrifice we finally were recently able to buy our house, with a pool, yes, chlorinated. And we’re patiently waiting for summer to enjoy it. Enjoy it we will. I see Pam’s anecdote above. As a counter-anecdote I basically spent every summer of my youth swimming in chlorinated water and being perfectly healthy. I know I know, but this really feels like beyond the point of diminishing returns, the world is out to kill us! So I can worry and worry and still die scared out of my pants, or simply die. I need some fresh air…
the information about vitaminC is fascinating — HOW does it do that? would it inactivate fluoride (another halide) as well? the latter is a constant irritant with me, being hypothyroid, and the fact that it can’t be filtered out of water, short of reverse-osmosis, which isn’t practical on a house-wide basis!
thanks, Chris! …btw, STILL love your Personal Paleo Code — i’ve learned that i have far more food sensitivities than i ever suspected.
Ascorbic Acid:
C5H5O5CH2OH + HOCL ==> C5H3O5CH2OH + HCl + H2O
Sodium Ascorbate:
C5H5O5CH2ONa + HOCL ==> C5H3O5CH2OH + NaCl + H2O
I used to have near death experiences in the shower.I’d get in and halfway through I couldn’t breath (asthma) and had to jump out of the shower and try to get breathing again. I started researching asthma and chlorine and finally figured out that the vapours caused by chlorine (and other stuff) hitting organic matter (my skin, etc) were causing severe asthma attacks. Installing a shower filter saved my life. When I mentioned this to my pulminary specialist (who has a presceiption pad perminantly embedded in his palm) he looked at me blankly and stated “well if you think it helps.”
I’m sure having the filter helps other areas of health as well but in my case as I mentioned before it literally saved my life.
Our shower and bath filters are in the mail. After doing research for a similar post on my blog, I got (very) concerned about the quality of our water and all the chlorine in it. When my kids bathe, the bathroom smells like a swimming pool. And my son’s skin has red spots on it after he’s done in the bath.
Recently, I have started getting red spots too, while I shower. And I realized today, that showers have been making me feel light-headed and a bit head-achy afterwards.
One thing that can help out just a bit is to also open your bathroom window whenever you can. That helps to get chlorine/chemical vapors out of the room. And the Vitamin C suggestion is excellent! I saw that somewhere else, while I was doing research as well.
You can get a filter for the bathtub.
Vitamin C as ascorbic acid, or will any form of C work?
Both ascorbic acid and sodium ascorbate will work.
Adding ascorbic acid will make the water more acidic, which is ok for bath water.
Sodium ascorbate is PH neutral, and is best for drinking water.
ttt, how much powdered Ascorbic acid to the bath water will do the job? thx
If the chlorine concentration is 1ppm, for every 100 gallon of water, you need 1 gram of ascorbic acid
I’ve wondered about this for awhile – chlorine in the steam from the shower, but I’d never read anything about it, let alone the potential harmful effects, until now. Thank you for posting this article. I’ll be ordering a shower head soon.
Loren Cordain’s newest book, The Paleo Answer has an entire chapter on water, chapter 12, with a section on in-home water purification systems and drinking water storage.
This post got me thinking back to when I was an athlete in junior and senior high. I was an all-year athlete and would compete in swimming in the winter but had been taking swimming lessons since early childhood. By the time I was in senior high I couldn’t stay on the team any longer because I would get physically ill when I entered the room with the pool. To this day I still get mildly ill when I smell chlorine, I can usually muscle through it when I take my kids to the public outdoor pool, but that’s nowhere near as nauseating as the indoor pools.
Could a lifetime of exposure to chlorine cause sensitivity to chlorine in the air? I’m not thinking of getting an in-house filtration system . . . *planning a budget*
Thanks for publicising this particular nasty. I’ve long ago sworn off swimming in chlorinated pools. Recently after earthquakes our city council chlorinated our pristine artesian municipal water supply for about 6 months. During that time, I took showers at my workplace which gets its water from an artesian well and daily lugged water home for cooking etc. as well as topping up our supplies from national parks. No way was I going to expose myself to that toxin, especially considering my auto-immune thyroid disease. Dr Mercola’s site alerted me to this environmental hazard.
So what about hot tubs then?? Chlorine and bromine and all that steam rushing up under your face? How to prevent that??? Any safe chemical approach for hot tubs?
i’m with commenter carlos. very interesting, but… i’m not going to do anything about this.
i played water polo and swam competitively for years. now what?
as the grateful dead put it, ‘if the thunder don’t get you, than the lightning will!”
We all have to choose our battles. But knowing what they are is important. If installing a relatively cheap shower filter can significantly reduce my exposure to harmful toxins, and using a vitamin C tablet in the bath can reduce my baby daughter’s exposure, it’s a no-brainer. But of course your mileage may vary. My job is to inform – what folks do with that information is of course entirely up to them.
Wow, goes to show you have to READ the article vs skim it. Off to buy 1,000 mg Vit. C tabs…easy!
Copper that is used for some water pipes can leach into the water if the pipes are old and not maintained well. This is one factor I’ve been told by my doctor to be aware of with treating copper:zinc imbalance which Chris has covered before.
What about the use of supplemental iodine to somewhat overcome the chlorine problem in regard to potential thyroid dysfunction ? Both fluoride and chlorine block iodine uptake.
I have a 4 yo with terrible eczema on his legs since 2 months old. It cleared up totally (and asthma too) when I removed dairy. It has been back this winter (& improved after going gluten free) but imagine my horror when a coworker told me that the cure for eczema is Clorox in the bath water! Apparently this is popular, and we work in healthcare.
Any suggestions for a fluoridated water supply? Reverse osmosis drinking water filters from Aquasana do not filter out fluoride.
From a quick glance at the Aquasana website, it looks like their drinking water systems are not reverse osmosis, which is why they don’t filter out fluoride. Reverse osmosis pushes water against a membrane that has pores that, for the most part, only allow water molecules to pass through. That removes pretty much all dissolved content, including fluoride. Get an actual reverse osmosis system, and you’ll remove the fluoride.
I think you are mistaken. I’ve never seen a reverse osmosis filter that actually filters out fluoride, because manufacturers assume, incorrectly, that this is something most people don’t want removed from their water. Care to point me to a reputable brand which shows on their website it removes fluoride?
It’s common knowledge that RO removes fluoride. Do a Google search on ‘reverse osmosis fluoride’ and you’ll find lots of links showing that RO removes fluoride. Here’s one such link:
http://chemistry.about.com/od/chemistryhowtoguide/a/removefluoride.htm
If, for whatever reason, you still don’t trust RO to remove fluoride, then get a distiller. Countertop distillers cost around $125 and up.
Chris,
Does the vitamin c apply to drinking water? We have a big berkey with an additional fluoride filter. We have chloramines here in LA and its been in the back of my mind that the berkey can’t take care of chloramines. Would adding vitamin c to our drinking water be warranted?
I work in oncology and have noticed many swimmers who were very healthy getting cancers such as lymphoma and breast cancers. There seems to be a cluster where I live. This scares me.
Well put. I cannot help but think that many of the things that we encounter in daily life, such as chlorine, we will down the line find out is bad for us. Especially over long periods. My family uses well water (we filter it anyway), buy locally, and we grow as much of our own food as we have time and energy.
Where is the proof that vitamin C and bath balls work?
Hi, thanks for the info. Corroborates with my own Internet research. But, I did come across the theory that vitamin C does neutralize chlolamine but with the byproduct of ammonia, which has its own hazards. Something to further research.
Awesome… I think I’ll just not bathe…. (kidding)
Chris,
Is there any way you could do an article on flouride in our water? There’s a lot of info out there, but a lot of it’s not well written or sourced.
…and then if you have a lot of time (as I know you do with a kid and all) maybe one on toothpaste too! Looking for good info on the use (or misuse) of glycerine.
Good dialogue (most of it anyway). True it is that everything that has benefits is also likely to have drawbacks, or unintended negative consequences, particularly when used excessively or without reasonable consideration of the mitigating factors.
My personal research into the issues of chlorine exposure, particularly in the contexts of normal bathing, swimming (recreational water exposures) and even domestic potable waters, has “opened my eyes” to numerous negative effects of chlorine on the human body than I ever took seriously before. Learning there are cost-effective and relatively minor adjustments that can be made to the water that we use and require, is how you start to relieve not only the symptoms and causes of health risks but also the anxiety and paranoia that comes with incomplete understanding.
As we age, we tend to either get wiser or we have events occur that bring into focus the inevitable fact of our mortality and eventual deterioration of our health. Prolonging our individual (and family’s) good health by reducing exposure to environmental toxins (like chlorine) is easier than I previously thought.
Shower and even whole-house filtration systems remove chlorine (and chlorine byproducts) and other risk factors very effectively and at very reasonable cost. Counteracting hardwater problems, without the health and environmental risks of salt-based softeners, is very well established today and even more economical.
Even for recreational waters (swimming pools, hot tubs, therapy spas, etc.) can be better served by combining limited amounts of chlorine (small amounts do have a beneficial effect) with copper-silver ionization treatment methods. This ionization technology was perfected by NASA and the space program over the last 4 decades. And it is recognized around the world as safe, more effective and far more stable than chlorine alone.
This is real, scientific and proven technologies that can mean better health to you and your loved ones and help your pocketbook at the same time.
The benefits and risks of chlorine (and other chemicals) in our water is akin to our culture of over-medication. Where a small dose of many commonly prescribed pharmaceuticals can save a life, too-large doses can either take a life or permanently and negatively alter the quality of that same life.
Learn what you can and take action. If you aren’t willing to take action to protect yourself, then I suggest you remain ignorant and enjoy as much of your life as you can (“Ignorance is Bliss”, someone said).
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