FLAGSTAFF, Ariz. — Disposable plastic water bottles in shops, vending machines, hotels and grocery stores at Grand Canyon National Park will disappear early next year under a plan by park officials to ban the sale of them.

But first they'll have to demonstrate they've met guidelines issued late Wednesday by the National Park Service that require a review of water availability, health and safety, cost and benefits, and get the approval of the regional director. Grand Canyon spokeswoman Shannan Marcak said Thursday that the park believes it already is positioned to comply with the guidelines.

"We need to fully review it, and it takes a little time to figure out if we have all those things covered," she said.

Park Service director Jon Jarvis nixed a bottle ban at Grand Canyon late last year just weeks before it was to be implemented and said the agency would develop a national policy. Former Grand Canyon Superintendent Steve Martin raised suspicions that the action was due to influence from the Coca Cola Co. — a major water bottle distributor — but the Park Service denied that.

"While superintendents need some discretion to tailor implementation to local situations, it is not the purview of any one park to set policy," Jarvis wrote Wednesday in memo to regional directors.

Marcak said Grand Canyon has been encouraging visitors to ditch disposable bottles in favor of reusable ones and to fill them at one of nearly a dozen water stations on the north and south rims that were installed at a cost of more than $300,000. She said the park hadn't yet gathered data to show whether the year-long effort resulted in a decrease in park waste, 30 percent of which is made up of disposable plastic water bottles.

Zion and Hawaii Volcanoes national parks have instituted bans similar to the one proposed at the Grand Canyon. The Park Service said those parks also would have to show in writing that the new guidelines are met and evaluate the bans annually.