The Environmental Working Group analyzed the company websites and product labels of over 170 varieties of bottled water to see if the companies disclosed information on where water came from, how the water was treated, and whether the results of tests to ensure purity were revealed.
The researchers also called the bottled water companies to see if they would willingly give information to consumers.
More than half of the bottled water products failed the transparency test. Almost 20 percent didn't say where their water comes from, and an additional 32 percent did not disclose any information on treatment or purity of water.
According to Yahoo Green:
"Only three brands earned the highest possible ... Gerber Pure Purified Water, Nestle Pure Life Purified Water, and Penta Ultra-Purified Water ...
[S]ix brands got the worst marks in EWG's report ... Whole Foods Italian Still Mineral Water, Vintage Natural Spring Water, Sahara Premium Drinking Water, O Water Sport Electrolyte Enhanced Purified Drinking Water, Market Basket Natural Spring Water, and Cumby's Spring Water."