We haven't had a post yet on the everlasting tap water versus bottled water controversy, have we? No? Well, then. The AP got all sorts of attention a few months ago when it discovered trace pharmaceutical amounts in the nation's tap water—at least 46 million Americans, it turns out, have contaminated water dripping out of their faucets. Mind you, it wasn't always clear whether this was even a danger in all cases ("the comprehensive risks are still unclear"). In some areas, the contamination only amounted to tiny traces of caffeine. In others, it might be more problematic, but no one quite knows yet. Still, it made for a good headline—and a topic for further study.

On the other hand, for anyone who might've read that headline and dashed out to stock up on bottled water, a new study out today by the Environmental Working Group found that leading brands of bottled water were… no cleaner on this score, and just as contaminated. Bacteria, caffeine, fertilizer, solvents, traces of pain reliever—all there. The bottle brands didn't violate any federal standards, mind you, although two of them would've failed California's more stringent tests. (Some of this might be due to the fact that companies like Coke and Pepsi just put tap water in their bottles in the first place—this accounts for about a quarter of all bottled water in the country.)

That's all on the heels of a nice piece Elena Conis did for the Los Angeles Times a few days ago on this long-running debate. Yes, tap water still has risks—even water that passes state standards with flying colors might still go on to pass through old pipes that leach copper and lead. But tap water's also tested much more frequently—and rigorously—than the bottled variety, and only tap-water suppliers have to circulate annual consumer reports on where they're getting their stuff. So it's a tie—until you get into costs and the fact that tens of billions of plastic bottles get tossed in the United States each year, using up about 17 million barrels of oil. (Fun comparison: that's about one-sixteenth of what we'd get from drilling in ANWR at peak production.)

--Bradford Plumer