Water_photoAfter a run, there’s nothing like that first sip of water for refreshment without the guilt. But an Environmental Working Group report states that 10 major brands of bottled water tested positive for pollutants ranging from chlorine and fertilizer residue to caffeine and arsenic. The levels found were as high as those found in tap water, and in some cases worse.

The report also notes that while tap water is subjected to regular testing for these harmful chemicals, bottled water manufacturers do not have to disclose their water-quality test results. So while the commercial may show a clear, mountain spring, a bottled water’s origins may not be nearly as appealing or healthy.

The Group’s recommendation: Fill up your bottle with filtered tap water for a refreshing drink that’s clean, convenient and cheap.