The next time you head to a national park, will you be able to buy a bottle of water?

Right now, it depends on the park. About 20 parks, including Grand Canyon, Mount Rushmore and Zion national parks, have banned the sale of plastic water bottles.

When the National Park Service introduced the optional no-bottle-sales policy, it seemed like a good way to get rid of the bottles, which cause litter — not to mention a recycling nightmare. Disposable plastic water bottles are the main source of trash in U.S. national parks, averaging nearly one-third of the parks' solid waste, according to a report by Protecting Employees who Protect Our Environment or PEER.

"Sustainability is a visible effort for the National Park Service," director Jon Jarvis wrote in a memo to all the systems' parks in December 2011. "We must be a visible exemplar of sustainability...When considered on a life-cycle basis, the use of disposable plastic water bottles has significant environmental impact compared to the use of local tap water and refillable bottles."

But what seemed like a good idea to environmental groups and park leaders didn't make companies that manufacture water bottles very happy. Known as "Big Water," the roughly 200 manufacturers of bottled water are fighting back.

They've mounted a big-time lobbying campaign on Capitol Hill, reports The Washington Post.

“This is a prominent, misleading attack on bottled water that has no justification,” said Chris Hogan, vice president of communications for the International Bottled Water Association, which represents the manufacturers and is leading the fight against the park bans.

The Post reports that the industry has found help in its campaign to stop restrictions on water sales. A new measure prohibits the park service from using taxpayer money to eliminate disposable plastic bottles in parks.

“Families who don’t own expensive camping equipment and aren’t experienced hikers and climbers will be surprised to find out that they can’t buy their child a bottle of water at one of our national parks,” U.S. Rep. Keith Rothfus of Pennsylvania said as he introduced the legislation. “Temperatures at the Grand Canyon just this week will top 100 degrees. Visitors who may have forgotten or have run out of water could be put at risk of dehydration.”

water bottles overflow in the trash at the National MallA recycling bin overflows with water bottles at the National Mall in Washington, D.C. (Photo: Mr.TinDC/flickr)

If not water, then what?

Of course the restrictions put a dent in water sales, but beyond that, the bottlers say the rules are "misguided." Park visitors who don't bring their own reusable water containers may be forced to buy sugary sodas and other drinks instead of water.

Jarvis acknowledged that possibility when he sent his memo.

"It eliminates the healthiest choice for bottled drinks, leaving sugary drinks as a primary alternative," he wrote.

Nutrition professor and registered dietitian Rachel Johnson, Ph.D., wrote an editorial in The Hill speaking out against the sales ban. She did a study when the University of Vermont, where she is employed, put similar rules in place in 2013. The result was a 33 percent increase in sales of sugary drinks and a 6 percent increase in the number of bottles shipped to campus, she says.

"Our study shows that these sorts of policies, regardless of the motivation behind their adoption, may result in the consumption of more calories and more added sugars, a perpetuation of unhealthy dietary choices, and — ironically — an increase in plastic waste," she wrote. "Our study clearly suggests that the NPS bottled water sales ban has the potential to undermine efforts to encourage healthy food and beverage choices and may be environmentally counterproductive."

little girl refilling her water bottle at Grand Canyon National ParkA little girl refills her reusable water at Grand Canyon National Park. (Photo: Grand Canyon National Park/flickr)

The disposable impact

Parks that have banned the sales of disposable water bottles have not banned visitors from bringing in their own water bottles (reusable or not) and have installed refilling stations. Some question whether the cost of buying and installing those refilling stations cancels out any savings created by the ban.

Zion National Park was the first to institute the sales ban. The NPS calls the move "a sustainability success story," saying that the park has eliminated the annual sale of more than 60,000 bottles of water, which is the equivalent of 5,000 pounds of plastic not entering the waste stream.

"Bottled water is advertised as a product born of pristine mountain springs and intended for the health conscious consumer. The truth, of course, is that the life cycle of plastic water bottles has a considerable environmental footprint," says a message on the National Park Service website.

According to the Grand Canyon's website, disposable plastic bottles comprise an estimated 20 percent of Grand Canyon's waste stream and 30 percent of the park's recyclables.

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Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.