Gary Kremen—the founder of Match.com, former owner of Sex.com, and serial investor—is into water. The entrepreneur started investing in water tech startups a few years ago. Today he’s an elected member of Silicon Valley’s water district, an agency that manages water and flood control for 2 million people. Earlier this year, he helped craft a proposal to build a tunnel under the Sacramento-San Joaquin River Delta that could improve drinking water reliability for cities from San Jose to San Diego.