Read This Before You Reuse that Water Bottle

The question before us today is: If my water bottle is just filled with clean water, why do I need to wash it?


Answer: Well, first off, if you are reusing that plastic water bottle day after day until it breaks apart into little plastic pieces, congratulations. We wish everyone did. It might seem obvious that, if your water bottle is simply filled with clean water, and you refill it with clean water, and you are the only one drinking from it, it’s not dirty, right?

This kind of reminds us of the bathroom towel question. If we are clean when we get out of the shower then how does our bath towels get so dirty?

bottled water

Photo credit: bigstock

Well, the answer to the plastic bottle dilemma is, not exactly. Most water bottles that are commercially made are intended for a single use. Manufacturers assume that you will drink the contents, and then toss the bottle.  In fact, manufacturers don’t even recommend that you try to reuse that bottle because every day wear and tear, including washing, can lead to an actual breakdown of the plastic, thinning out the plastic or even developing tiny cracks, cracks too tiny to see or to leak, but cracks that can hide bacteria.


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If you ask manufacturers they will suggest that you don’t reuse it, but if you must, they suggest that you wash them regularly in hot (but not too hot) water and use mild soap and ensure that there is no physical breakdown of the bottle that you can see. Once you can actually see the damage, they suggest you toss it.

Even those plastic bottles that are sold or marked as “reusable” could be contaminated with bacteria, especially if you don’t wash them or if you reuse them in spite of visual evidence of wear. Unfortunately, bacteria are nasty little suckers that love to hide in the cracks and even the scratches of surfaces. This can pose an even bigger health risk that the possibility of chemicals from the plastic leeching into the water.

Oh, you should also know that those nifty little water bottles are a real haven for bacteria. A study published in 2002 in the Journal of Public Health showed that when researchers took samples of water from 76 different water bottles among elementary school children and it found that some of the bottles had been reused for months and had never been washed. Not surprisingly, more than two thirds of those water samples had bacterial levels that were higher than the drinking water guidelines suggest is safe. This may have been the result of bacterial regrowth in bottles that remained at room temperatures for long periods of time. This study was carried out by researchers from the University of Calgary.

Although this study did not examine the exact source of the bacteria, the most likely source came from the hands of the students themselves. Of course this means that inadequate or improper hand washing after using the restroom at school could easily result in fecal matter being present on those water bottles. Unwashed bottles are a great breeding ground for bacteria.  Bacteria love to grow quickly in the right conditions, such as nutrients from “backwash”, moisture, and warmer temperatures. Unwashed bottles have all these things going for them.


In a non-scientific study, news station KLTV took samples from water bottles that had been used, but not washed, for one week. Cultures were taken from the necks of these bottles. The University of Texas Health Center told KLTV that every single bottle had lots of bacteria. Enough to give someone the worst possible kinds of  symptoms, similar ones to food poisoning, the kind that cause vomiting, diarrhea, and nausea.

Ok, so right about now you are saying to yourself “I’ll just dump my bottles in the dishwasher from now on. Problem solved.” The problem here is that washing most plastics in the kind of hot water temperatures that your dishwasher puts out isn’t a problem but disposable bottles are not made to withstand those kinds of temperatures. Heating bottles to that temperature will only increase the rate at which chemicals can leech into the water from the plastic itself.

Never reuse any plastic container with the recycling number of 7 as these contain BPA, a known carcinogen that can leech into the liquids or foods that are placed inside these types of plastic containers.


SEE ALSO: BPA Free Plastics Contain Another More Dangerous Chemical


Now, of course this doesn’t mean that you should never reuse a water bottle. We only have one Mother Earth and we need to dump less trash on her) However, you can be more strategic about the kinds of bottles you buy and reuse. Glass bottles with protective frames around them, as well as stainless steel bottles work well. If you must use a plastic bottle, buy the kind made from polypropylene, which are typically white, not clear. These types of plastic are non-reactive, which means that they don’t spill their chemicals into your drink if they get overheated or left alone for long periods of time. Many labs use polypropylene for this reason. And although it’s impossible to find out if the manufacturer had put in some kind of additive or plasticizers to their product, you can pretty much bet it’s going to be a safer bet than your everyday disposable bottle. If you still want to reuse that plastic water bottle, please do. Just be sure that you take the time to wash them, by hand, with hot water, and let them dry overnight. Find out how to use less plastic and go green.

Pass this information on to your friends and family who tend to reuse plastic water bottles. Because friends don’t let friends vomit for days because of a dirty water bottle.