Michael Burry, one of the guys that shorted the house market in 2008, started to invest in water since 2013
From Wiki: "In 2013, Burry reopened his hedge fund, this time called Scion Asset Management, filing reports as an exempt reporting adviser (ERA) active in the state of California and approved by the SEC.[19] He has focused much of his attention on investing in water, gold, and farm land. He has said, "Fresh, clean water cannot be taken for granted. And it is not—water is political, and litigious."[20]" https://en.wikipedia.org/wiki/Michael_Burry