Damon himself got a slow start working on the issue.
"I had produced a documentary about people running across the Sahara desert, these ultra-marathoners, and had used it as a chance to identify NGOs that were doing good work around water," he said. "My idea was to partner with these local communities, with these groups we vetted.
"At any rate, we were raising funds and directing them to the NGOs basically for well projects. As I learned more about it I started to realize there were these other incredibly innovative solutions that actually had a much better chance of solving the problem."
His next step: "I finally said, can somebody please introduce me to the world's foremost expert on this, who's actually doing something about it. That guy wasn't available. But they introduced me to Gary."