Hey Mr. Green,
My office has four cases of half-liter water bottles delivered each month. Would a water cooler be greener? — Ezra in New York City

Mr. Green answers:
Water coolers aren't just good spots for catching up on the latest office gossip. Those jugs generally get reused, while 80 percent of the 25 billion plastic water bottles manufactured every year (using 1.5 million barrels of oil) are thrown away.

Bottled water is an inspiring example of marketing genius; it might also be the craziest form of privatization yet imagined. We're buying plain old H₂O at hundreds, or even thousands, of times the price of tap water because advertising images of clear mountain springs have us convinced that what's inside plastic containers is purer or healthier than what comes out of the faucet.

In fact, it's generally not. According to the Natural Resources Defense Council, more than 25 percent of bottled water sold in the United States is taken from the same public water systems as tap water. And federal standards for bottled water are pretty much the same as for tap; though lead content in bottled water is more strictly monitored, tap water is tested much more often for other contaminants. If you're concerned about the purity of your tap water, check out the EPA's local water-quality reports at epa.gov/safewater. A good certified filter (nsf.org) can take care of most problems at about ten cents per gallon. (If you have well water, however, the Centers for Disease Control and Prevention cautions to get it tested first.)

Filtering your water or refrigerating it overnight in a loosely capped glass or ceramic container will dissipate any chlorine taste or odor, though issues with the flavor may be primarily psychological. In a Good Morning America taste test, New York City tap water beat out bottled water, as it did in other tests I've looked at. So maybe all your office needs is a change of mind-set. For more information, go to sierraclub.org/committees/cac/water/bottled_water