Raw water trend slammed by food safety expert: 'You can't stop adults from being stupid' A bizarre new trend has emerged in California's Silicon Valley, with people eager to buy large glass containers filled with unfiltered, unsterilized H20, billed as "raw water" by the company selling it for $36.99 (£27.21) for 2.5 gallons, and $14.99 for a refill. The trend was discovered in San Francisco by The New York Times and prompted a response from food safety expert Bill Marler. Marler told Business Insider: "Almost everything conceivable that can make you sick can be found in water." He warns that because safe drinking water has become the norm, people are unaware of how dangerous natural, unclean and untreated water can be. "The diseases that killed our great-grandparents were completely forgotten about," he said. "It's fine until some 10-year-old girl dies a horrible death from cholera in Montecito, California." Untreated water can lead to the spread of diseases like cholera, E. coli and Hepatitis A, which killed 20 in California during an outbreak last year. Giardia, another illness caused by unclean water, puts roughly 4,600 US people in hospital every year. "You can't stop consenting adults from being stupid," Marler added. "But, we should at least try."