By Michelle Singletary
Sunday, July 15, 2007; F01

I used to bathe my daughters together when they were little.

To tell you the truth, I didn't wash them together just to save time. I was trying to save money and water. I might still force the issue, even though my 12-year-old would be horrified at the thought.

Okay, I wouldn't do that to her. But American families could save about $170 per year by retrofitting their homes with water-efficient fixtures and appliances, according to the Environmental Protection Agency.

That may not sound like a lot to some. But as I always say, when you sweat the small stuff, the money adds up.

Being environmentally friendly has a double impact. You save money and the planet. That point was driven home to me by former vice president Al Gore's recent documentary, "An Inconvenient Truth." If more of us paid attention to the things we waste, we wouldn't have as many of the global environmental issues as we're dealing with now. Plus, we'd have a little more left in our wallets. And it's not just being water-wise that can help you save a few bucks. What about the trash you throw away?

In 2005, U.S. residents, businesses and institutions produced more than 245 million tons of municipal solid waste, according to the EPA. That translates to about 4.5 pounds of waste per person per day. Invite me to a party and it's likely I'll go through the trash to rescue recyclable plastic and cans.

In light of my conservation mood these days, I thought I should make my annual Penny Pincher of the Year Contest a themed challenge. This year, I'm looking for penny-pinching entries that have a positive impact on the environment.

For example, one of my all-time favorite penny pinchers is Louise Meyer of the District. She won the first Penny Pincher of the Year Contest in 1997 by writing about how she put solar cookers on her roof and used them to fix chicken, rice, stuffed peppers, even pasta.

At the time, Meyer said she saved about $40 a month on her electric bill during the winter and $140 in the summer months by solar cooking her food and not using her clothes dryer and air conditioning.

To solar cook, all you need is a sunny day, water-resistant, aluminum-laminated cardboard, a clear plastic oven-roasting bag to create a mini-greenhouse effect, and a dark pot with a tight-fitting lid for maximum heat absorption. To find out more, visit the Web site for Solar Cookers International ( http://www.solarcookers.org), a nonprofit organization based in Sacramento. For less than $50 you can buy a solar cooking kit, which includes a cookbook.

I try to be considerate of our country's hardwood forests by reusing every delivery box that arrives at my house. When I have to mail a package, I just go to my closet where I keep recycling and regifting items and look for the right size box (I also recycle the protective packing material). I use labels to cover up the old shipping information.

Another previous penny-pinching champion took a plastic milk jug into the shower with him to capture the cold water that came out before the water heater kicked in. He then took the cold water and used it to fill his toilet tank to flush. By doing this, he was able to cut his water bill.

In this country, we use an average of 100 gallons of water a day at home. We could cut our water use by 30 percent. If all U.S. households installed water-efficient appliances, the country would save more than 3 trillion gallons of water and more than $17 billion dollars annually, the EPA says. And when we use less water, we reduce the amount of energy needed to supply that water.

So what's your best energy, water or waste-saving penny-pinching story? You can nominate yourself, a family member, friend, relative or co-worker. I'm looking for originality and honesty. I'm interested in frugal folks, not misers. Humor scores big in this contest.

To reward those who are serious about saving money and the environment, there will be cash prizes. First place wins $100, second $75 and third $50.

Please take note that edited versions of entries may be published whether you win or not. Anonymous entries will not be eligible. Send your entries by Aug. 20 to colorofmoney@washpost.com. Please put "2007 Penny Pincher of the Year Contest" in the subject line. Please include your full name, address and daytime and evening phone numbers. You can also mail entries to Michelle Singletary, Color of Money, 1150 15th St. NW, Washington, D.C. 20071. If you are sending your entry via regular mail, please put on the front of the envelope "Penny Pincher of the Year Contest."

· On the air: Michelle Singletary discusses personal finance Tuesdays on NPR's "Day to Day" program and online athttp://www.npr.org.

· By mail: Readers can write to her at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071.

· By e-mail:singletarym@washpost.com.

Comments and questions are welcome, but because of the volume of mail, personal responses are not always possible. Please note that comments or questions may be used in a future column, with the writer's name, unless a specific request to do otherwise is indicated.