A study published yesterday in the proceedings of the National Academy of Sciences of the United States of America (PNAS) has analyzed trends in drinking water violations over the past 34 years; estimating that between 9 and 45 million people were impacted each year during the time period.
High level takeaways from the study include:
Some drinking water contaminants cause immediate illness - there are 16 million cases of acute gastroenteritis (diarrhea, vomiting, and flu like symptoms) annually at US community water systems.
State agencies do not have a procedure to select water systems for additional inspection and monitoring.
The Southwest is a region of high concern; Oklahoma and Texas had the most community water system violations between 2004 and 2015.
In 2015, up to 21 million Americans may have drank unsafe water.
Small, low-income communities are most susceptible to contaminated water systems.
Violations drastically increased in rural areas in the early 2000s after the EPA created regulations focusing on disinfectants - chlorine and other chemicals that kill microbes in water supplies. Disinfectants can react with organic matter in water to create new compounds that pose health risks.
Environmental groups have claimed this study may be on the conservative side of the problem.