The average American home has 10,000 items in it. We need storage units and cabinets in just about every room to house all these things. But you would need an Olympic-size swimming pool to store all the water it takes to make what we so casually call our stuff.

In fact, if you were to release all the water in all the items in our homes, at least 200,000 gallons would gush out like in some mad scene in a disaster movie. Americans expend a lot of water spending $78.5 billion a year on furniture. Heres why: Most of the furniture we own (38 percent) is made of wood. Just 1 board foot of lumber takes about 5.4 gallons of water to make. Wood, of course, comes from trees, and last time I checked, it took water to grow trees.

A full-grown pine tree, for example, needs thousands of gallons of water to mature to a size thats ready to be chopped down for timber. Most timber wood comes from trees more than a decade oldit takes that long to get big enough to be felled. Its one thing if that timber is derived from trees in a sustainably farmed forestone that is cared for and maintained so trees can grow anew for decades or centuries. The Forest Stewardship Council (FSC) certifies companies that adhere to responsible management processes. But most timber trees arent so lucky. As much as 40 percent of the worlds timber supply comes from illegal logging. These illegal loggers chop down trees without regard for the soil, the water tables, or the futures of the forests. They wreak havoc on the environment, ruining chances for new trees to grow and resulting in the loss of water that we cannot easily recapturegreen water.

Green water is precipitation that falls on trees, soil, and grassy areas but escapes our capture and direct useits stored in such forms as soil moisture, and trees can harvest it, but we cannot.

Blue water is the water that ends up in rivers, lakes, aquifers, and other bodies of water that we can easily tap into.
The chair you are sitting in right now, for example, likely took more than 44,000 gallons of green water to make. If the trees it took to make that chair werent sustainably harvested, then more trees wont grow in their place and that amount of green water in that region is lost.

Buying secondhand furniture is great way to stem the drain on virgin materials. Theres certainly plenty of vintage from which to choose. The US Environmental Protection Agency says theres an 8.8-million-ton pile of furniture at our landfills. So next time you hear some inane furniture-store ad claiming that its prices cant be beat (!), or that your mattress will be free (!!), or that you wont have to make payments until 2060 (!!!), remember that there are other prices to pay -- environmental prices -- for buying something new.

Photo by Nature Form Furniture via Flickr. Thomas M. Kostigen is the author of The Green Blue Book: The Simple Water-Savings Guide to Everything in Your Life (Rodale). www.thegreenbluebook.com.