The Green Challenge: CO2 meets H20.

The Green Challenge: CO2 meets H20.

The Green Challenge: CO2 meets H20.

Help the planet.
May 21 2007 12:37 PM

Water Works

CO2 meets H2O.

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Illustration by Robert Neubecker. Click to launch this week's action quiz.

Think water and global warming, and melting Arctic ice caps may come to mind—a problem that can seem pretty insurmountable. But the water in your sink and dishwasher and bathtub also has a CO 2 cost associated with global warming. And it is a cost you can reduce. Using less water means less waste and pollution. Using less hot water means fewer CO 2 emissions. The average American household expends about 14 percent of its energy usage on heating water, according to the Natural Resources Defense Council. That adds up to nearly 4 percent of the country's total energy use and spins off about 260 million tons of carbon dioxide emissions.

A lot of excess water simply goes down the drain. Then there are gushy toilets and showers. According to the Rocky Mountain Institute, Americans with inefficient fixtures and appliances use about 80 gallons of water per person per day inside their homes. Replacing old and conventional faucets, washing machines, toilets, and showers with energy-efficient and low-flow varieties can stanch the flow by as much as a third—and you'll also trim CO2 emissions. How you heat up water makes a difference, too. Our suggestions for washing away your CO2 sins:

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• If you have an old or conventional shower head, switch to a low-flow version and save gallons of water a day. (Learn here how to check the flow rate of your existing shower head and replace it with a low-flow one.) Some low-flows deliver excellent water pressure with only 1 to 2.2 gallons per minute (as opposed to the current government standard of 2.5 gallons per minute or pre-1992 shower heads that use even more water). Aerating, low-flow shower heads mix air into the water stream to maintain steady water pressure. Nonaerating shower heads deliver a stronger spray and tend to pulse. Both types of fixtures can cost as little as $20; the money you'll save on your energy, water, and sewer bills will likely repay your investment in less than a year. Check out some TreeHugger-recommended brands here.

• A bathroom-sink faucet need deliver only 0.5 to 1 gallon of water per minute. In the kitchen, you want 2 or 2.5 gallons per minute so you won't get frustrated when you're filling pots. If your faucets are higher pressure and ready to be replaced, pick a lower-pressure model.

• Showers account for two-thirds of all water heating costs. The shorter your shower time, the more CO2 you'll save.

• Take showers instead of baths, which use more water.

• Turn the water off while you shave.

• Unless your dishes are really dirty, scrape instead of rinsing them before loading them into the dishwasher, especially if your dishwasher automatically prerinses or has a rinse-hold cycle. Also, use the energy-saver option, let the dishes air-dry, and, if possible, choose the light or cold-wash option. And wait until the dishwasher is full to run it.

• Which is more efficient—you or the dishwasher? Machine bests man in this debate: Hand-washing uses an average of 10 to 15 gallons of water, while automatic dishwashers use about 8. If you don't own a dishwasher or need to wash pots by hand, don't let water run while you're scrubbing.