TORONTO - Bottled-water companies will be the first to pay a conservation charge for profiting from Ontario's water, but all commercial and industrial users will eventually be hit with the levy to help protect the future of the Great Lakes, the government said Tuesday in announcing legislation that critics criticized as vague and "a shell."

The Safeguarding and Sustaining Ontario's Water Act would implement a deal with Quebec and eight U.S. states to ban almost all transfers of water outside the Great Lakes basin, and would slap a conservation charge on companies that border the lakes and use the water for profit.

Premier Dalton McGuinty said bottled-water companies are being targeted first as "just one small step forward," but other businesses should prepare to pay at a later date.

So-called "highly consumptive" users will be the next to pay the levy that's expected to generate about $18 million a year, Broten said.

But critics complained the government hasn't fully outlined its plans, and said the whole announcement seemed hastily put together in anticipation of the October election.

New Democrat critic Peter Tabuns said the government is trying to paint itself green any way it can, and he predicted the details still wouldn't be finalized before the province goes to the polls.

The government had promised in 2003 to stop "the reckless giveaway of Ontario's water," and it's now scrambling to get something done before election campaigning begins, he said.

"There's an election coming - they want to look as though they've done something," Tabuns said. "They want to look as though they've delivered on a promise. But there's no substance here - there's a shell."

Ontario, Quebec, Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin signed the Great Lakes-St. Lawrence River Basin Sustainable Water Resources Agreement in December 2005, and committed to drafting legislation to ban the diversion of water outside the Great Lakes Basin.

Ontario Environment Minister Laurel Broten said the deal ensures Great Lakes water isn't depleted or destroyed forever.

"Clearly our water is a precious resource and today we are taking the next logical step," Broten said.

"Any company that profits from our careful stewardship of the water supply should pay their fair share towards managing that supply; that's only right."