Along a windy road through oak woodlands, large properties in Corral de Tierra are surrounded by scenic terrain and often exceed $1 million. It’s an upscale rural community, but 45 of its residents face a major health issue: Their drinking water is contaminated with arsenic.
The levels of arsenic in the Corral de Tierra Estates water system – 72.5 parts per billion – are almost eight times the legal limit, making it the second-highest arsenic concentration in a residential area in California, according to a study conducted by the nonprofit Environmental Integrity Project made up of former EPA enforcement attorneys. The system has been noncompliant with U.S. Environmental Protection Agency standards since at least 2011.
While arsenic is naturally occurring in groundwater, there are ways to filter it out, but treatment can cost hundreds of thousands of dollars, and disposing of arsenic waste can be hazardous. But compliance is crucial due to the chronic health issues that can arise from long-term exposure to arsenic. Those who drink water with Corral de Tierra Estates’ arsenic levels have a 1 in 375 chance of developing cancer in their lifetime, compared to 1 in 2,000 for someone exposed to the EPA’s legal limit of 10 parts per billion.
To resolve this, some households in Corral de Tierra want to try in-house water treatment systems, but that would not fix the EPA compliance problem.
“People are allowed to put in in-house treatment systems if they want, but the water [system] needs to come into compliance,” says Cheryl Sandoval, who heads Monterey County’s small water system program. “The individual treatment system at this point would not put them in compliance.”
According to the EIP study, a Prunedale water system was also among those with the highest levels of arsenic in the state, but Sandoval says it met EPA drinking water standards over the past two months.