WASHINGTON, D.C. — America’s national parks have long influenced consumer habits with their decisions on what products to sell — or not sell — on park property. To help the bottled water industry, Congress wants to nip that influence in the bud.

At the behest of the International Bottled Water Association, Congress is preparing to approve a must-pass budget bill that includes language aimed at restoring the sale of water in disposable plastic bottles in all national parks.

For nearly six years, national parks have had the option of banning bottled water sales as a way to reduce plastic litter and waste management costs. From Cape Hatteras to the Grand Canyon, more than 20 park units have instituted the ban after first installing public drinking-water stations for visitors carrying reusable bottles.

For the last three years, the bottled water industry has lobbied Congress to help overturn the ban.

“It’s a fairness issue,” said Jill Culora, a spokeswoman for the bottled water association. She notes that the bottled water prohibition doesn’t extend to soft drinks and other refreshments in plastic bottles, putting her industry at a disadvantage.

Supporters say there is wide evidence the ban is reducing litter and waste at national parks. They say the bottled water companies are lobbying hard on the issue because they fear the ban could eventually spread from national parks to state parks and recreation areas.

“People look to our national parks as leaders in sustainability,” said Lauren DeRusha, a campaign director with Corporate Accountability International, a group that has long battled the bottled water industry. “When a national park takes a stand and says it doesn’t support bottled water … that is a big threat to the industry.”

Concerned with overflowing trash bins, the National Park Service implemented its bottled water policy in 2011 as part of a larger “Green Parks Plan.”

Then NPS Director Jonathan B. Jarvis instructed superintendents of more than 400 parks, monuments and historical sites that they had the option to end sales of bottled water. First, however, they had to install water refilling stations and offer sales of reusable containers.

By 2013, Grand Canyon and other parks were implementing the ban, and that’s when the bottled water industry sprang into action. Up until 2013, the association was spending roughly $120,000 a year on lobbying. Those expenditures tripled in 2014 and had jumped to $580,000 by 2016, according to federal lobbying reports compiled by the Center for Responsive Politics.

In 2015, Congress added a rider to a budget bill instructing the National Park Service not to expend any federal funds on the bottled water ban. Many parks were able to sidestep the restriction by installing drinking fountains with funds raised from outside organizations.

Last year, Congress ordered the National Park Service to produce a report justifying why some parks had continued with the ban. This year, Congress has gone a step further, ordering the National Park Service to suspend further implementation of the policy and “examine opportunities to partner with nongovernmental entities in developing a comprehensive program that uniformly addresses plastic waste recycling systemwide.”

In lobbying to reverse the policy, the bottled water industry — along with some health advocates — has argued the ban will encourage park visitors to buy sugary sodas, which remain available for sale. “Promoting greater consumption of water from all sources, including bottled water, will support the efforts of park visitors striving for a healthier and active lifestyle,” the association said in a statement.

DeRusha responded that “it is disingenuous” for the association to make such claims, given that its membership includes soda makers such as Coca-Cola and Pepsi, which also market bottled water. She and other advocates argue that many hikers and other visitors to national parks won’t opt for sodas if they can easily fill up containers — for free — from water stations.

As in past years, the budget bill language opposing the water bottle ban came from the House Appropriations Interior Subcommittee, which is chaired by a California congressman, Rep. Ken Calvert, a Republican from Riverside County. In 2016, Calvert was a top recipient of campaign contributions from the bottled water industry, receiving $10,000, and those donations became an issue in his re-election campaign.

Calvert couldn’t be reached immediately for comment, but during his campaign last year he said his legislative action stemmed from “concerns with the park service policy that allows the sale of bottled soft drinks but bans the sale of bottled water.”

National parks advocates say they regularly contend with budget riders that micromanage how the parks conduct their operations.

“It is hard to pass these egregious riders as standalone legislation,” said Ani Kame’enui, director of legislation and policy for the National Parks Conservation Association. “They don’t have the votes. That is why these things get tucked into must-pass bills.”