Matt Damon was conflicted when friends Jimmy Kimmel and Ben Affleck called on him to complete the ALS ice bucket challenge. The award-winning actor wanted to help a good cause, but didn't want to waste clean water in the process.

So, he did what any good humanitarian would do: He used toilet water instead.

The ice bucket challenge, which calls on participants to donate toward research of ALS (amyotrophic lateral sclerosis, or Lou Gehrig's disease) or dump a bucket of ice water over their heads within 24 hours of being challenged, presented a dilemma for the Water.org co-founder. The nonprofit is dedicated to providing clean drinking water and sanitation solutions to those in underserved regions of the world, so naturally, wasting even just one bucket seemed unnecessary.

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"It posed kind of a problem for me, not only because there's a drought here in California," Damon explained in the video, uploaded to the organization's YouTube channel. "But because I co-founded Water.org, and we envision the day when everybody has access to a clean drink of water -- and there are about 800 million people in the world who don't -- and so dumping a clean bucket of water on my head seemed a little crazy."

The actor -- who nominated George Clooney, Bono and NFL quarterback Tom Brady to do the challenge next -- said swapping clean H2O from the faucet for toilet water seemed fitting for the causes near and dear to his heart, as about 2.4 billion people across the globe still lack access to clean sanitation systems. Toilet water in westernized nations, Damon added, is still cleaner than the drinking water in many underserved communities in developing countries.

The ice bucket challenge has raised an unprecedented amount to combat the fatal neurodegenerative disease that affects nerve cells in the brain and spinal cord. Between July 29 and Aug. 25, the ALS Association has raised $79.7 million from about 1.7 million donors in its fight against Lou Gehrig’s disease, according to TIME. During that same period last year, the organization raised about $2.5 million.

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