Colonies of bacteria in your house…in your water bottle…in your water filter

I read today that 99% of bacteria live in colonies and attach to surfaces as biofilms. If you carry a reusable water bottle you might open it and rub your finger along the inner surface. My bet is that you’ll feel a slick coating on the inside surface of the bottle. That is biofilm, a colony of bacteria.

80% of all infections in humans come from biofilms according to Veysel Berk at UC Berkeley in a study published in the July 2012 issue of Science. A single bacteria is able to attach to a surface, start reproducing, and launch a reproducing colony that becomes a biofilm. 

Bacteria’s ability to reproduce is one reason I advise private well owners that treating their well using chlorine or even hydrogen peroxide is only a temporary solution. One must kill every individual bacteria, which is highly unlikely, or the colony will reestablish itself. A whole house UV light provides protection from bacteria entering the home. If you install the UV light at the same time you disinfect the well then you have provided a more long term solution to the problem of bacterial contamination of well water.

Most bacteria are harmless to humans. Still…that is not always the case. For instance there is the newly prominent brain eating bacteria that is the scourge of Neti Pot users (see article below). But most are harmless: your showerhead, your bathtub faucet, and even your kitchen faucet is home to colonies of bacteria which get flushed out each time you turn them on. That’s why it’s good to run a bit of water before filling a container or jumping in the shower. Faucets can be treated by dipping them in vinegar. This is accomplished by hanging a small bag containing vinegar on the faucet or showerhead.

Bacteria can also colonize your water filter. For this reason I employ KDF media in my kitchen water filters. KDF creates an anti-bacterial environment within the filter using a small electrical charge, or ionization. Some people use carbon impregnated with silver as a bacteriacide. I don’t like this approach because I suspect that drinking the silver can kill the beneficial bacteria in your body.

It is a good idea though to clean your filter housings with every filter change. I recommend filling each housing with hydrogen peroxide and then running water to the filter faucet and letting it sit. The hydrogen peroxide will oxidize, or consume, the bacteria or biofilm. This is another reason I don’t recommend using the same filter for multiple years even though it may have some contaminant removal capacity remaining. It’s a good idea to change filters and clean the housings annually because the inside most likely does contain a colony of bacteria.

If you’re using a water bottle repeatedly you might stop right now and soak it with a solution of half vinegar and half water to kill bacteria. Water bottles become contaminated from our hands and from our mouths. So you have to clean them often. After you do, stick your finger inside and see if the film is gone. Now that you’ve touched it, you’ll need to clean it again. Even though bacteria are everywhere and most are harmless to humans it’s a good idea to take small precautions such as these to keep them in check.

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About James McMahon

Studied ecology at the University of Illinois, mountain survival at Eastern Washing University, Deep Ecology at Naropa, River Ecology with The Nature Conservancy and Luna Leopold
This entry was posted in Best Water Filter, Exposure to Toxins, Healthy Drinking Water, Healthy Living. Bookmark the permalink.

57 Responses to Colonies of bacteria in your house…in your water bottle…in your water filter

  1. Vicky minich says:

    I will never use one if these again.

  2. Stevann Hamilton says:

    H2O2 and vinegar are great “common sense” control measures to consider in reducing bacterial contamination in homes. I’m going to use this post in my unit on denaturing enzymes where my students treat H2O2 with catalase, the enzyme that breaks down H2O2 in our bodies. One of their conclusive questions addresses this idea in terms of why we put H2O2 on our wounds to control bacteria. Now we can take it a step further by applying this to cleaning things we use in our daily lives.

  3. Kristi Lee says:

    I already subscribe to your Blog, so does that get me an entry in your Drawing?
    I also shared your post to my Facebook page. Does that get me an entry in the drawing?
    Hope you have a Wonderful Christmas!

    • Hi Kristi –

      Sure I’ll enter you, but just be fair to everyone else.

      The point of asking people to post to my blog is to create a dialogue in which we all learn from one another.

      One reason I know so much about water is due to the number of people I speak to every day about the water issues they’re experiencing.

      Each day I learn something new that helps me offer better solutions to everyone.


  4. Suzanne says:

    Hi Jim. Funny I should read this today. Yesterday, I laughed at my husband for refusing to drink out of the water bottle (stainless steel) I keep in my car. He asked if it was fresh. I replied that it was probably a couple weeks ago, but ok as I drink from my bottle sitting in my car often. I live in a cool climate and thought that the water is sealed, not getting heated, etc. so was ok. Can’t say I won’t ever drink from my car bottle that has been sitting for awhile, but I will make more of an effort to clean the bottle. periodically with vinegar.

    Thanks Jim, and I appreciate your educating me.

  5. Dave Lockhart says:

    Thanks for the reminder, with all the day to day activities, the hustle and bustle I forget to clean my water bottle on a regular basis. Happy holiday

  6. Joanna Browne says:

    Hello from Puerto Rico, we’re building a house here and plan on harvesting the rainwater. I’ve done some research, but still have not sent the water to be tested. Your drawing for Christmas motivated me to at least ‘start the process’. Thanks for your information, (and please enter me in your drawing?)

  7. JP says:

    Thanks, Jim. Curious about the UV ~ know they use it to treat the municipal water supply in Los Angeles, but then it has to travel through miles of pipes to get to our faucets, so it probably picks up a bunch of other stuff on the way, so a house filter is necessary. Also essential for the fluoride that they just added to the supply (neurotoxins, anyone?).

    Is water exposed to sunlight (the original UV) thereby disinfected? I know that sun exposure usually grows green things (algae, presumably), but I am not sure whether this is bad for us, or relatively harmless. The bacteria is the thing, and I find that being supported in the diet with pre- and pro-biotics helps as well.

    I usually sterilize my glass reusable bottles with boiling water before refilling, and cleanse my teakettle by soaking then boiling vinegar and water in it (which has the added benefit of removing scale). Sterilization kills the bacteria as well, yes?

    • Hi JP –

      There is some form of sunlight disinfection but I’m not familiar with it.

      The fact that exposure to sunlight results in algae just shows that there is algae there to begin with, along with bacteria not killed by the chlorine and chloramine used by Los Angeles. My Urban Defender whole house water filter with catalytic carbon plus my custom reverse osmosis system are the tools to use to make LA water safe and healthy to drink.

      Boiling would kill the bacteria and that’s one method used by campers when drinking stream water.

  8. Keith Burton says:

    Jim, thanks for helping to keep us healthy with your informative articles. As I always say “When it comes to clean water, Jim McMahon is the source to tap into.”

  9. Emilie Nottle says:

    Is there a concern about bacteria when leaving
    distilled water in glass bottles with lids, for a few
    days or weeks? We don’t drink from these bottles
    (we pour the water out into a glass or pot for cooking).

    If so, is there a way to control the bacteria?

    • Hi Emilie – I would think that if the bottles were clean to begin with, as in sanitized, you would be ok. I don’t know of any way to control bacteria inside the bottle other than something like iodine or a bit of bleach and I wouldn’t use either of those myself.

  10. Karyn Osterman says:

    Thank you Jim for the pointer on vinegar to disinfect water bottles used over and over. My favorite bottles come from a lemonade container with an attached cap with a rubber seal. I have been rinsing them with very hot water between uses and have noticed the biofilm you talk about. Seems like a vinegar rinse is just the solution I was looking for.

  11. Brad Novacek says:

    I was suspect to of when you change your filters often. I thought is was just to make more money for the filter companies. Now i realize that it’s because of bacterial growth. Something i’ve been suspect of in my father-in-law’s house RO undersink system. Too bad you can’t refrigerate the RO system some how to reduce the baterial growth.

    My thought was since winter is coming here in Oklahoma I could install the filtering equipment against the outside wall under the sink for a little bit more cooling than on the side facing the dishwasher. Just a thought.

  12. Carol says:

    I hope that I win your Kitchen Defender as it sounds like I need it after reading this post. It would be both a great birthday gift (it is my birthday today) and important to my recovery following my surgery this week. I would think that I would have a lower resistance to fight bacteria after surgery. I am wondering if I should use a vinegar and water rinse after dish washing in chlorinated water. Wish me luck. Also, have a wonderful vacation with your son.

    Thank you, Carol

  13. mellie says:

    Well, Jim. It’s good to know that I have been doing at least something right! I use vinegar to clean almost everything, and when I finish a plastic bottle of water, I spray it inside and out with 100% vinegar and let it sit overnight before refilling. Sometimes I can taste a little vinegar from around the edge, but I know it won’t harm me. And there is never any kind of film. Some people may think I am crazy, but I want to be as healthy as possible. Thanks for the tips!

  14. Suzanne says:

    Hi Jim,

    Thanks for this post. My son just started Kindergarten and my frustration is that they often send the kids to the water fountain or give them tap water. It is so hard to control once your kids start public school. If you have any suggestions or know of schools in the US who have tackled this problem, do let me know (or may be worth a blog post?).

    all best,
    Suzanne in New Jersey

    • Suzanne –

      When I was in school I took a lunch box and a thermos. Nowadays I take my filtered water from home whenever I leave the house. I’d ask if he can do that.

      And I’ll ponder your suggestion.


  15. Marilyn says:

    Thank you, Jim, for this insightful post. I always learn something useful here. Vinegar and baking soda are the two cleaning staples I use in my house, along with ammonia on a limited basis.
    Happy Holidays!

  16. Cecil says:

    Hi Jim,
    How long do you need to soak a water bottle for to kill the bacteria?

    thanks for the info, Cecil

    • I slosh the vinegar around inside the bottle and pour it out through the spout making sure to hit every surface. And I let it sit for several hours if I have that kind of time. Then I pour baking soda down my kitchen drain and pour the vinegar in after that to clean out the drain of lingering bacteria build up.

  17. Anne Stewart says:

    That’s a nice blog about water, and water filters… and why one should clean out water bottles! Bottle brushes were created to physically remove biofilm. If you use a water bottle you should use a bottle brush regularly. Biofilms are the perfect growing environment for many pathogenic bacteria, and not only in water bottles but cooling towers, air conditioners, the tray under your fridge, especially the tray under your drum-style humidifier or inside a portable room humidifier (if you have one/use one – most house do not need humidification), and anywhere condensation collects (perfect for mold growth, especially if it drips onto materials which are cellulose-based – paper, drywall, cardboard, etc.)

  18. Ed Kingham says:

    I’ve recently heard a health advocate recommend finding a spring near your home and collecting drinking water from it once or twice a month. I like the idea, but I wonder about the bacteria content. Do you have a recommendation on where to get spring water tested?

  19. Maggie Roos-Codsi says:

    25 yrs ago we started using a water filter +uv light system in Taiwan. So we
    have been very attentive to your regular email messages, enough to recently recommend you to a friend in NC whose immune system is so compromised
    she is currently battling numerous GI tract bacteria. The whole house system you are
    preparing is the only thing giving her hope this will be the last time!
    And thanks for the water bottle tip! That could be part of the problem for her and
    certainly a reminder for me!

  20. Susan Nichols says:

    I just finished cleaning my water bottles with dish soap and a bottle brush. Is the vinegar soak in addition to routine washing?
    Also, would clothes washing machines be harborers of bacteria as well? (We cleaned out our front-loading washer this weekend, primarily the drainage tubes, the pressure tube connector, and the rubber water seal boot area around washer tub. They were full of sludge….)
    Thanks for a Christmas drawing!

    • Susan –

      I use vinegar instead of dish soap in part to avoid a soapy residue or taste in the water bottle. The vinegar is in place of using soap.

      That sludge would likely harbor bacteria but it would be in the drain lines. You could fill a load with washing soda or vinegar but no clothes just to clean the machine.

  21. Cathryn Farr says:

    Thanks for the opportunity to win one of your products. Our well water changes throughout the year and this time of the year it smells funny. I keep planning on getting one of your systems, but with a house full of teenagers there is always something squeaking louder than the water faucet!
    I enjoy the information you share.

  22. Lisa argueta says:

    I have been drinking reverse osmosis water that I fill up weekly in three gallon bottles .unfotunately it it is the best I can do due to my budget constraints. I have always instinctually not been able to drink water left over from water bottles worrying about bacteria. How worried should I be about the bacteria lurking in my 3 gallon r/o water?

  23. Connie says:

    Thank you so much for keeping us informed. What you say makes since and a lot of times things that I know but just get busy and forget. I love reading the blogs. Keep them coming. Enjoy the new year!

  24. Tanya Eldridge says:

    We use vinegar on just about everything…laundry, counter tops and even in the dishwasher but I never thought to soak our our stainless steel water bottles in vinegar. Thanks for the tip and good advice!

  25. AnneB says:

    I had noticed the film in my stainless steel water bottles and my animals bowls but did not know what it was. I will be quicker to clean them now. This is true even though I use local spring water for drinking. Interestingly, I get green mold in my chicken waterers with city water and not with the local spring water. However, the film is the same. Thank you for the information.

  26. Lynn Parks says:

    Jim, your articles are always so informative without being too wordy. Thanks for all you do…it is appreciated.

  27. Jennifer says:

    I’ve noticed that film before! It’s when I definitely think to myself “I need to wash this…”, though I suppose I should be washing it more often so it doesn’t get that way to begin with! I’ll definitely do the the vinegar solution. I actually stopped using store bought detergents/soaps and make my own now–use vinegar in the rinse cycle. Probably not quite as effective or proportionate.

  28. Elissar says:

    Dear Jim,

    Thank you very much for all of your work and the knowledge that you give. I’ve just introduced my mother to your website and ressources and we are looking into a water filtration system and air filtration system for the whole house.

    And thank you for this opportunity to be entered into the draw! I would like to receive updates on your blog and I will definitely like you on facebook.

    Blessings and Peace,

  29. Glenn Katzung says:

    Hi James,
    I’ll start a daily cleaning regiment with vinegar instead of dish soap from now on in my stainless water bottle, and also my camel back hydration pack when I use it.

    Thanks James for the great info

  30. I just washed out my glass water bottle – yuck! I hope the soap did the trick. Do you think stainless steel and glass repel bacteria better than plastic? I want to go research that now.
    I’ve wondered about the RO system under my sink, since Culligan says we don’t need to change those filters very often… years, actually.

    • Hi Bethany –

      I think all bottle types are the same when it comes to biofilm.

      Quite surprised to hear Culligan recommending that length of time between filter changes. That seems odd to me.


  31. Elizabeth Corbell says:

    Hi Jim,

    OK. I figured out how to blog, so this time I’m doing it right (I think).
    How often should we clean our water bottles? I have one of those bottles with a straw that I use at work and in the car. Once a day? Once a week?

    • Elizabeth – good work! Now you’re a blogger. I clean my water bottles about once a week by filling it half full, or a bit more, with vinegar and then filling to the top with water.

  32. Christyna says:

    Vinegar is such a simple, but POWERFUL natural cleaner. Thank you for this reminder!

    My imperfect filtered water is still better than drinking unfiltered water from the tap, isn’t it?

    • Hi Christyna – you won’t get me to endorse the wrong water filter. Just call me and we’ll figure out what you ought to have by finding your local water report. Perhaps by chance you do have the right water filter. Because, frankly, I have concerns about drinking a number of contaminants on a daily basis. So it’s best to know. At least that’s my story and I’m sticking to it. 🙂

  33. Amanda Harvey-Schwartz says:

    Hi Jim,

    Thank you for this info. I had been cleaning out my stainless steel bottle with hot water and a bottle brush, but I will certainly be switching to the vinegar and water solution you suggest. A friend had suggested using a saltwater solution for disinfecting the bottle. How effective would that be? And I have noticed a buildup of red film on the drain in my kitchen sink and on all water-touched surfaces in my bathroom. Would wiping these down with a vinegar solution daily to weekly help eradicate the problem?

    • Hi Amanda –

      I’d not heard of the salt water solution. Vinegar makes more sense to me.

      As for the red film in wet areas that is due to an airborne bacteria that lives in moist environments. I don’t know of any way to avoid it other than not allowing moisture to sit, which can be a challenge in a humid environment. I wipe that down weekly with vinegar in my house.

  34. Cheri Katzung says:

    I’m assuming that my Berkey water filter would also build up this film. Can I clean it (including the black charcoal filters) with vinegar and water? Or would that be destructive to the filters?

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