Diamond Valley Lake plays a critical role in the well-being of Southern Californians. When major droughts befall the region, the reservoir is among the first emergency resources to be tapped for fresh water, and it can sustain Southern California's 18 million inhabitants for up to six months.

Otherwise, the lake is much more about having fun, and Diamond Valley Marina helps people do just that. Though bodily contact with the water is not permitted, visitors can rent a boat from the marina and cruise across the 7-square-mile body of water surrounded by red hills. The fishing alone is reason enough to make a visit to Diamond Valley, and many do every year to try and haul up the black bass, bluegill, rainbow trout, and catfish that live beneath the waters, brazenly breaking the clearly stated no-body-contact laws. Nonfishers, meanwhile, can be content with relaxing on a rental pontoon from the marina or hiking or riding horses on the trails that rim the lake edge.