WATER SECURITYSafe Drinking Water Remains Out of Reach for Many Californians

An estimated 370,000 Californians rely on drinking water that may contain high levels of the chemicals arsenic, nitrate or hexavalent chromium, and contaminated drinking water disproportionately impact communities of color in the state, finds a new analysis led by researchers at the University of California, Berkeley, and the University of California, Los Angeles.

Because this study is limited to three common contaminants, results likely underestimate the actual number of Californians impacted by unsafe drinking water from other compounds for which data are not as widely available, the researchers say.

Since 2012, access to safe, clean and affordable drinking water has been recognized as a human right in the state of California. Community water systems are required by federal regulations to undergo regular testing for contaminants that are harmful to human health. However, many California community water systems do not meet regulatory standards. In addition, many largely rural households receive their tap water from private domestic wells that remain largely unregulated.

This study, published in the current edition of the American Journal of Public Health, is the first to quantify the average concentrations of multiple chemical contaminants in both community water systems and domestic well areas statewide and is the first to systematically analyze demographic disparities in drinking water quality across the state.

The authors stress that addressing inequities in access to safe, clean drinking water will only become more urgent as climate change brings prolonged droughts and limits water availability in the state.

An estimated 370,000 Californians rely on drinking water that may contain high levels of the chemicals arsenic, nitrate or hexavalent chromium, and contaminated drinking water disproportionately impact communities of color in the state, finds a new analysis led by researchers at the University of California, Berkeley, and the University of California, Los Angeles.

Because this study is limited to three common contaminants, results likely underestimate the actual number of Californians impacted by unsafe drinking water from other compounds for which data are not as widely available, the researchers say.

Since 2012, access to safe, clean and affordable drinking water has been recognized as a human right in the state of California. Community water systems are required by federal regulations to undergo regular testing for contaminants that are harmful to human health. However, many California community water systems do not meet regulatory standards. In addition, many largely rural households receive their tap water from private domestic wells that remain largely unregulated.

This study, published in the current edition of the American Journal of Public Health, is the first to quantify the average concentrations of multiple chemical contaminants in both community water systems and domestic well areas statewide and is the first to systematically analyze demographic disparities in drinking water quality across the state.

The authors stress that addressing inequities in access to safe, clean drinking water will only become more urgent as climate change brings prolonged droughts and limits water availability in the state.

“The goal of the Drinking Water Tool is to provide timely access to data that can inform efforts to protect the state’s drinking water and groundwater supplies, particularly in disadvantaged communities where the threats are greatest,” said study first author Clare Pace, a postdoctoral scientist at UC Berkeley. “We’d like to continue to refine the Drinking Water Tool in collaboration with the Community Water Center and in response to feedback from other organizations and decision-makers who can help ground-truth the data.”

The tool also allows users to compare drinking and groundwater quality information with data on community demographics across the state and models how drought conditions may impact water availability for domestic wells and community water systems that serve fewer than 10,000 people.

“In this era of climate change, our groundwater is becoming an increasingly precious resource, and we’re facing historic levels of drought and well failures. Even if a well doesn’t fail, drawdown of the water table can impact water quality by concentrating contaminants, making these problems even worse,” Cushing said.