Hey Mr. Green,

My husband says that we are not wasting water when it goes down the sink drain or we have the lawn sprinklers on because it just goes back into the aquifer/ground water.  How do you see it?

—Jane, in Chico, California

I hope he’ll take it graciously, but he’s wrong. First, some of that water will evaporate before it ever gets to an aquifer, especially with the blazing heat in your corner of the universe. Second, depending on the type of soil and rock in a given area, it can take years—even centuries—to reach an aquifer, so he might not even be around to enjoy the hypothetical fruits of his wanton watering. (Clay soil and shale, for example greatly slow the movement of water down into aquifers.) Third, if he believes that water returns to aquifers, how does he explain estimates from the U.S. Geological Survey that the water level in the gigantic Ogallala Aquifer in the Great Plains has dropped 100 feet in some areas? Or that, close to home, how some parts of  California’s Central Valley have sunk down as much as 25 feet, thanks to the fact that at least 12 cubic miles of water—or a cool trillion gallons—have been pumped from the groundwater supply.

I hasten to add that your local water supply is a matter of very special concern to me, because your town hosts one of the finer microbreweries in the land, and high-quality water is essential for good beer. Since the microbrewery is arguably one the 20th century’s greatest contributions to humanity, its water supply is vital to civilization itself.--Bob Schildgen