Peter Thum and Jonathan Greenblatt are driving across the country in a big blue bio-diesel bus to sell bottles of cold water. But they're not just trying to raise money for their company, Ethos Water. In every city they visit, they get out of their bus, walk around the downtown area, and talk to anyone who'll listen about what people in other parts of the world go through to get a drink of water.

"The world water crisis is one of the world's largest problems," says Peter Thum. "It affects a billion people around the world. That's four times the population of the United States."

Peter Thum became aware of this problem a few years ago, when he was working in South Africa as a management consultant. When he returned home, he decided to do something about it.

"I had this idea that it was possible to create a company, Ethos Water, that could help connect people in the developed world with solving the problems in the developing world," says Mr. Thum. "So, I reached out to my business school classmate and my friend Jonathan Greenblatt and we started this company."

Mr. Greenblatt says by producing and selling bottled water here in the United States, their company is generating money to help children around the world get clean drinking water. "We were running the company from my son's bedroom in my house in Los Angeles," he says. "We were building it one store at a time, delivering water out of the back of a beat-up borrowed Volvo station wagon and created our little company, which was mainly bankrolled by the two of us for a long time. We funded it with our credit cards and our saving accounts."

Three years later, Ethos Water is on more solid financial footing. It has partnered with non-governmental organizations and funded water projects in developing countries from Africa to South Asia to Central America.

"Last year, Jonathan and I flew to Honduras and went to the village of Cholusnate where we funded a water project for a village of about 125 families," he says. "The people in that village had never had clean water access. This water project enabled them to have the materials to obtain water from about 5.5 kilometers away from their village. The water then goes into a tank where it's stored and filtered again. Then, the water goes down to a sink at every home so every single family has the ability to get clean water to drink, to bath their children, and to prepare food with."

"[Ethos Water] is a good example of a partnership we'd like to expand and work in a number of countries," says Vanessa Tobin, who is in charge of UNICEF's Water, Environment and Sanitation programs. Ms. Tobin says the lack of clean water impacts peoples' lives in many ways. "In many countries," she explains, "people don't have access to such basic needs as safe water even to wash their hands to prevent diseases, to cook, drink. In rural areas, women and girls can be walking three or four hours to collect water, which stops young girls from going to school, stops women from being able to do other tasks. We also estimate about nearly 5,000 children under the age of 5 die every day as a result of diarrheal diseases due to poor sanitation and lack of safe water."

Since 2002, Ethos has donated about $100,000 of its sales to international water projects. Ethos was sold earlier this year to Starbucks Coffee Company, but its mission continues under the sponsorship of the new owner. Supporting the world water cause will ultimately bring more profits to Starbucks.

David Hessekiel is president of the Cause Marketing Forum, which connects companies with charities. He says this phenomenon is called 'cause-related marketing,' and it has been around for over 20 years. The concept became widely known in 1983, when American Express, the credit card company, created a major campaign to support the renovation of the statue of Liberty and the Ellis Island landmark in New York. At that time, they linked usage of their card to contributions to those projects, and raised close to $2 million, while also seeing tremendous increases in their business.

Over the years, he says, this approach of "doing well by doing good" has become a successful - and popular - marketing strategy.

" We're living at a very exciting time in cause marketing," he says. "What was once the domain of the few very idealistic companies perhaps, is now being recognized by the largest companies in the world as an important aspect of how you do business. Not only do you need to satisfy shareholders, but you need to satisfy customers, to keep your employees feeling that they work in a good environment. Cause marketing efforts and corporate social initiatives are a wonderful way in which businesses benefit, causes benefit, and society benefits."

That's exactly what the Ethos Water founders hope to achieve through their 10-week Walk for Water. They began their campaign August 3 on the East Coast, in New York City, and will end it September 29 in Seattle, on the West Coast. They say the people they've met so far feel good about buying a bottle of water, knowing their purchase will help others around the world enjoy drinking clean water, as well.