How Safe is Our Water

The United States has for the most part, safe drinking water available to all. Incidents that I have written about, Flint Michigan, Charleston WV, Toledo, OH and the frequent “Boil Water Alerts” that are occurring in towns and cities highlight the challenge for our community and city water systems to provide 24/7 safe drinking water with aging infrastructure and the reluctance to prioritize spending to maintain our water infrastructure while our source water (both groundwater and surface water) continues to be impacted by all the chemicals our modern life uses.

In Flint, potentially 98,000 residents were exposed to elevated levels of lead, disinfection by-products, E. coli and Legionella bacteria. In Charleston, a leaking above ground chemical storage tank released 4-methylcyclohexanemethanol (MCHM) mixed with 5.6% propylene glycol phenyl ethers (PPH) into the Elk River, the source water for Charleston, West Virginia. In Toledo, Ohio unregulated toxins formed during algal blooms though to have been caused by agricultural runoff into Lake Erie forced the community to close the water intake for the city.

In the United States approximately 86% of the population obtains their water from public water supply. Over the past decades, the frequency of water quality violations under the Safe Drinking Water Act have increased. In a paper published early this year in the National Academy of Sciences, Maura Allaire, Haowei Wu and Upmanu Lall examined the national trends in violations of the Safe Drinking Water Act. As you can see below in the chart from their paper. 

from Allaire et al.

The authors found that “in 2015, 9% of community water systems had health-based violations of water quality standards. This affected nearly 21 million people in 2015. During the years 1984-2015 the authors found that 9–45 million people were affected in each year, representing 4–28% of U.S. population. “Drinking water contaminants pose a harm to public health. Some can cause immediate illness, such as the 16 million cases of acute gastroenteritis that occur each year at US community water systems. ..Health-based drinking water quality violations are widespread, with 9–45 million people possibly affected during each of the past 34 years...Though, relatively few community water systems (3–10%) incur health-based violations in a given year.”

From the U.S. EPA website the total number of serious violations for the past  four years has been decreasing slightly since 2014. Note though that the total number of "serious violations" from the EPA data charting tool appears higher. The number of water systems with any violation is more than 10 times higher.  

from US EPA

If you want to read more about concentration and location of water system violations the full paper cited below can be read at the link. 

National trends in water quality violations

Maura Allaire, Haowei Wu, Upmanu Lall

Proceedings of the National Academy of Sciences Feb 2018,115 (9) 2078-2083; DOI: 10.1073/pnas.1719805115