After all, fresh water is finite - merely about one percent of all water on earth.
Water experts widely view water as the next oil. The irony of diminishing fresh water even as we face rising seas does not escape them.
Conservation is not just a drop in the bucket. New York had a campaign in the 1990s and cut water use up to 20 percent.
Several groups have come up with a way to save even more water. They've coined a term: virtual water.
It's the water implicit in the energy we use: up to 2 billion gallons a day to refine petroleum in the United States, for instance.
It's the water in the things we buy: 32,000 gallons on average to produce the steel for a car, 101 gallons to produce a pound of cotton for clothes.
It's the water in what we eat: 60 gallons to produce one pound of corn, 287 gallons for a pound of chicken - enough to drown the poor creature many times over.
Several advocacy groups have a Web site, www.h2oconserve.org, which provides the statistics above - as well as a test to measure your "water footprint," which humiliated me.
By my tally - I have a well, so it's trickier - my husband and I use 100 gallons a day.
(Aqua America, the region's main suburban supplier, reckons about 140 gallons average daily household use.)
The calculator decided the two of us actually use, in effect, 2,083 gallons a day.
The test got personal, wanting to know if I let the yellow mellow in my toilet.
It asked if I donate my old clothes; trashing them is like "flushing gallons down the drain."
It grilled me about recycling. Not tossing a pound of paper saves 3.5 gallons.
Coffee and shoes
Another calculator - at the European site www.waterfootprint.org - makes it possible to parse the virtual water for a cup of coffee (37 gallons) versus tea (8).
This test even asked my income so it could make bold assumptions about things I might buy. Such as leather shoes: 2,113 gallons.
This is pretty esoteric. And my inner skeptic balked at feeling guilty over shoes that were on sale anyway.
How is this different from when my mother told me to eat my broccoli because children in Biafra were starving? Besides, if we all switch from coffee to tea, will displaced Colombian workers be forced into the drug trade?
I called one of the H2O sponsors - GRACE, a public awareness group.
I confess that I baited them, telling them if I didn't use my water "it's just going to flow into the Atlantic and get salty anyway."
They were, of course, aghast. Four people got on the phone at once and I could barely sort out the sputtering.
They cited statistics. They talked about moral imperatives - a theme I heartily espouse, except I didn't let on.
Their bottom-line message: We really are running out of water. The population and usage are growing.
In the end, I'm hardly going to buy a car based on the water to make the steel instead of the gas mileage it gets. But I'm definitely going to pay more attention.
And I have one more reason to appreciate the ripe tomato on my kitchen counter. I grew it in my yard, with my water.
Contact staff writer Sandy Bauers at 215-854-5147 or email@example.com. To post a comment, visit her blog at http://go.philly.com/greenspace.