After we’ve drained a Dasani bottle, many of us will just fill it back up from the tap without a second thought. But can you reuse plastic water bottles, really?
Plastic water bottles don’t seem to be going anywhere fast. In fact, Americans are drinking somewhere in the neighborhood of 13.7 billion gallons of bottled water each year (that’s more than 36 gallons per person), according to an August 2020 Research and Markets report.
But you might want to reconsider reusing plastic water bottles. Research suggests that sipping from single-use containers for multiple days can lead to bacterial growth, chemical leach and avoidable waste. Read on for the 101 on your H2O.
Types of Plastic Water Bottles
Not all plastic bottled water is the same — different brands and containers can be made from different materials.
You can tell what type of plastic a product is made of by checking the triangular recycling code stamped on the bottle, which can also help you determine if the bottle is recyclable by your local program, according to the Environmental Protection Agency (EPA).
Most water bottles are made from polyethylene terephthalate or high-density polyethylene (more on that later), according to an August 2019 study in Environmental Science & Technology . Here’s the breakdown of these and other common plastics:
Your Water Bottle Could Harbor Yucky Germs
So, is it safe to reuse plastic water bottles? As it turns out, a days-old Dasani bottle is the ideal breeding ground for bacteria.
“After two days or so, colonies of microorganisms will form a biofilm, similar to the way barnacles adhere to a boat,” says Philip Tierno, PhD, clinical professor of microbiology and pathology at NYU Langone and author of First, Wear a Mask: A Doctor’s Guide to Reducing Infection During the Pandemic and Beyond.
This slimy coating is made up primarily of your mouth bacteria (plaque on your teeth is actually a type of biofilm), but can also potentially contain waterborne pathogens as well as germs from your hands that contaminate the water when you’re unscrewing the cap. And when you take a drink, your mouth may come into contact with the germy outer surface of the bottle.
You can reuse plastic water bottles — but only to a point. “You can refill the bottle as often as you like for 24 hours, but then discard it,” Tierno says.
In an August 2018 study in the Journal of Exercise Physiology , researchers compared 30 used disposable water bottles belonging to gym-goers and 30 new, unopened water bottles. None of the new water bottles had bacterial contamination, while 90 percent of the used bottles contained pathogens, including E. coli.
Now you may be wondering whether you can get sick from reusing plastic water bottles. Well, “E. coli indicates that you have transmission from feces into the water, and where you find fecal matter you can also find other organisms like salmonella and norovirus, [a stomach bug],” Tierno says. “While these organisms may not in and of themselves cause an infection, there is always the potential.” Plus, it’s just gross.
“After two days or so, colonies of microorganisms will form a biofilm, similar to the way barnacles adhere to a boat.”
And these days, with concerns about catching COVID-19, you have to take extra precautions.
“People shed their passport of germs wherever they go,” Tierno says. “Although COVID is spread primarily through aerosols, surfaces do come into consideration.”
Whether you put your water bottle down on a bacteria-filled public surface, carry it past someone who is talking or coughing or hold it with unwashed hands when you’re on-the-go, you’re exposing it to contamination.
“Use a wipe to periodically sanitize the outside of your bottle, the same way you would your cell phone,” Tierno says.
Can you just wash a disposable container at the end of the day to clean off the biofilm and other germs so that you can reuse the water bottle?
“During COVID, I wouldn’t recommend it,” Tierno says. “If these were normal times, you might be able to get one more day’s use out of your bottle by washing it with warm, soapy water.”
And definitely don’t sip from it for longer than 48 hours.
“The thin plastic that disposable bottles are made of has grooves, nooks and crannies that make it impossible to get rid of the biofilm,” Tierno says. “In fact, most bottles have labels that say, ‘do not reuse.'”
In comparison, reusable metal or glass bottles are much easier to clean thanks to their smooth, flat surface.
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