See, in addition to being a popular and likeable celebrity, Matt is also the cofounder of Water.org, an organization dedicated to providing the world with clean water. That is to say, Matt feels strongly about the same kind of water that everyone has been wasting with this charity event. So you had the gut feeling that he wouldn’t be dumping fresh drinking water all over himself.
Smartly, Matt kills two birds with one stone by also addressing a subsection of the clean water issue: sanitation. He ends up scooping and dumping water from toilets upon himself — after all, our toilet water is cleaner than most third world countries’ drinking water. Powerful, right? It’s gross, but it certainly also makes a good point: don’t shake Matt Damon’s hand.