CNBC: With surface water supplies decimated from the ongoing drought, more Californians are forced to use groundwater.
But groundwater is unsafe for nearly 800,000 residents, according to the state's water resources control board.
This problem is the longtime contamination from nitrates and arsenic.
That's meant less drinkable water in California's struggle to survive more than three years of severely dry weather.
"Most areas affected by contamination don't have surface water supplies so they...