ABC News' Haley Muse reports:

Matt Damon spoke with ABC News' Cecilia Vega during an interview on "This Week," about his philanthropic efforts to provide worldwide access to clean drinking water, and information about the importance of toilets.

An estimated 2.5 billion people lack access to improved sanitation, and 780 million lack access to clean water. It was staggering figures like these that prompted Damon to co-found the non-profit water.org in 2009.

"It's just so huge," Damon said. "There's a real opportunity to save a lot of people."

Since its inception, water.org has provided safe drinking water and sanitation across three continents by building wells and toilets through donations and microloan programs.

"It's really hard for us to relate to it in the West," Damon said. "A clean glass of water is as far as the faucet and we all have toilets."

Damon is using his fame, and some bathroom humor, to bring the issue to light.

In a viral YouTube video, "Matt Damon Goes on Strike," Damon declared, "Until everybody has access to clean water, I will not go to the bathroom." He also enlisted some celebrity friends to take the fictitious pledge, including A-Listers Jessica Biel and Bono.

All jokes aside, the Oscar-winning actor wants people in the West to understand the severity of this global issue.

"Every 20 seconds, a child dies because they lack access to clean water and sanitation - not here," Damon said. "Our kids aren't going to die from diarrhea. That's just an inconvenience to us in the West. But it is a stark, terrifying reality to billions of people on the planet."

Through a hands-on, community driven approach, Water.org works with the local communities through the entire building process, starting with a loan, or what they refer to as "WaterCredit."

"Instead of just drilling a well and giving it to somebody for free, what we're looking at is how do we help them get access to a small loan, so that they can get a water connection at their home from the local utility and become a customer," Water.org co-founder Gary White said.

Their approach is working. Damon said that of the roughly 250,000 loans Water.org has provided, 98 percent have been paid back in full. As loans are repaid, funds can be redistributed to others in need, reducing the need for subsidies, and allowing parents to work and children to go to school instead of spend their days fetching water. Those who are affected most, Damon said, are girls.

"Girls are the ones who do the water collections," he said. "Girls are the ones who are leaving school and not going to school because their job is to fetch water for the family. If you can get them access to water then the outlook for that girl completely changes. Suddenly, she can have hope for a bright future rather than a future that basically exists around trying to scavenge for water to survive to the next day."

While Water.org has made a significant impact, Damon said this is still a timely issue that needs more attention.

"People's lives are at stake," he said. "These deaths are unnecessary, yet children are still dying by the millions."

Visit water.org to learn more.

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