Can I Reuse My Plastic Water Bottles?

Disposable Water Bottle

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Single-use plastic water bottles are everywhere. As they are easy to refill from the tap or water cooler, you will often see people reusing these plastic bottles despite warnings that they should never be reused.

Two dangers are typically cited with these warnings. The first is that chemicals might leach from the plastic into the water you are drinking. The second is that bacteria can grow in the bottles once they are opened.

But are these dangers founded on science? Learn the facts about how you can safely use a reuse a disposable water bottle.

Chemical Leaching Fears and Dangers

Disposable water bottles are usually made of polyethylene terephthalate (PET). As of 2020, there is no solid evidence that reusing PET water bottles raises the risk of chemicals leaching into the water. However, you should always throw away bottles that have cracks or are showing other signs of degradation.

PET has been tested extensively and no evidence of migration of toxic amounts of chemicals from the plastic to the contents has been found.

PET is approved for both single-use and repeat-use as a drink container by the Food and Drug Administration (FDA), Health Canada, European Food Safety Authority, and other health and safety agencies worldwide.

One substance causing concern is antimony, a potentially carcinogenic metal that is used during plastic manufacturing. Many studies have looked into whether antimony will leach into water or food that is stored in PET bottles or containers.

A review of studies from 2010 found there was only a slight migration when water was stored in PET bottles at room temperature for three years. The amount was found to be only 1% of the tolerable daily intake that is established by the World Health Organization (WHO).

Bottles that have been subjected to higher temperatures might have an increased amount of leaching, but the research is not conclusive. While some experiments have found leaching, it has been far below the amount that is believed detrimental to health.

A large review of studies that was published in 2012 found that research on the subject often had contradictory results, likely because researchers used a variety of research protocols and analytical methods.

Many warnings about reusing water bottles stem from the widespread publicity given to a 2001 master's thesis from a University of Idaho student.

The student suggested that chemicals leach from the plastic used for single-use bottled water bottles into the water if the bottles were reused and subjected to light, heat, and time.

However, the study was not subject to peer review or published in a scientific journal.

Bacterial Concerns for Reusing Water Bottles

The real culprits surrounding the safety concerns of reusing any water bottle are the bacteria and fungi that can grow in damp or partially full bottles once they have been opened.

Bacteria in a water bottle will generally come from your hands and mouth, but can also come from dirt that comes in contact with the mouth of the bottle. Manufacturers of single-use water bottles note that if you reuse bottles, tiny cracks can develop. Bacteria and fungi can grow in those cracks, making it more difficult to remove them by cleaning.

However, the same applies to any drinking container—not just plastic. Glass, metal, or reusable plastic bottles can also develop bacterial growth and become more of a challenge to keep clean over time.

Cleaning Your Water Bottle

Both single-use and reusable water bottles should be thoroughly cleaned and dried between uses. Reusable water bottles generally have wider mouths, making them easier to clean. Dishwashing soap and hot water are acceptable to use for cleaning your water bottle.

The risks of bacterial and fungal growth are higher if you use the bottle with a drink that contains sugars. Immediately drain, rinse, and wash your water bottle after you have used it with sports drinks or juices.

Sanitizing Your Water Bottle

If you have visible bacterial slime or mold in your water bottle, you should sanitize your water bottle with a dilute bleach solution of 1 teaspoon bleach and 1 teaspoon of baking soda in 1 quart of water.

How to Clean Your Water Bottle

  1. Mix 1 teaspoon bleach + 1 teaspoon of baking soda in 1 quart of water.
  2. Pour the solution into your bottle.
  3. Allow the solution to sit in the bottle overnight.
  4. Thoroughly rinse the bottle.
  5. Let the bottle dry completely before using it again.

Bisphenol A in Reusable Bottles

Following concerns that bisphenol A (BPA) could leach out of clear polycarbonate water bottles, most bottles have been reformulated to be BPA-free. If you have any clear, hard plastic water bottles labeled #7 that are 10 or more years old, they might have been made before this change. Bottles that are more than 10 years old should be replaced.

A Word From Verywell

It should be safe to reuse a disposable water bottle as long as it is in good shape without cracks or signs of wear, and you keep it clean. While single-use plastic water bottles are convenient, you still might consider investing in some good reusable water bottles, which are often easier to keep clean and, as an added bonus, come in a number of materials, sizes, shapes, and colors.

Whichever you choose, be sure that you're drinking enough water to prevent dehydration. Now that you know the facts, don't avoid drinking water because you are afraid of the water bottle.

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Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Welle F, Franz R. Migration of antimony from PET bottles into beverages: Determination of the activation energy of diffusion and migration modelling compared with literature data. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2011;28(1):115-26. doi:10.1080/19440049.2010.530296

  2. Bach C, Dauchy X, Chagnon M-C, Etienne S. Chemical compounds and toxicological assessments of drinking water stored in polyethylene terephthalate (PET) bottles: A source of controversy reviewed. Water Research. 2012;46(3):571-583. doi:10.1016/j.watres.2011.11.062

  3. Raj SD. Bottled water: How safe is it?. Water Environ Res. 2005;77(7):3013-8.

Additional Reading
  • Lilya, D. Environmental Engineering Program. Society for Risk Analysis 2001 Annual Meeting.