🚰 The share of polluted drinking water in the US has been cut in half

🚰 The share of polluted drinking water in the US has been cut in half

The share of readings in American drinking water that exceeded health limits fell by half between 2003 and 2019. A new study has mapped 266 million readings of 1,250 different pollutants and shows how investments in water systems lower pollution levels.

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  • The share of readings in American drinking water that exceeded health limits fell by half between 2003 and 2019.
  • A new study has mapped 266 million readings of 1,250 different pollutants and shows how investments in water systems lower pollution levels.
  • The investments also reduced mortality among older Americans.

The most comprehensive mapping to date

A group of researchers has compiled the largest body of data on pollution in American drinking water ever used in research. Through Freedom of Information Act requests and collection from state agencies, they obtained 266 million readings. The material covers 1,250 different pollutants in 48 states over several decades.

The background is the Safe Drinking Water Act, introduced in 1974. Between 1970 and 2014, public and private sources spent around $2 trillion on clean drinking water. The law regulates 90 substances, while industry uses more than 42,000 chemicals. Nine out of ten American homes get their water from public water systems, and the country has about 150,000 such systems.

Pollution is declining

The results show that the share of readings exceeding current health standards fell by half between 2003 and 2019. Radionuclides and disinfection byproducts declined the fastest.

The researchers also examined 9,200 measures that water systems carried out with the help of subsidized Safe Drinking Water Act loans. The measures cut the share of readings violating health standards by nearly 10 percent. When they targeted a specific pollutant, the share of readings above the limit for that substance fell by 36 percent.

The researchers calculated the cost. For an average water system, it would cost $3.4 million a year to eliminate all readings above the health limits for regulated substances. That amounts to $46 per person per year.

Lower mortality among older adults

The researchers linked the water data to medical records for Americans over the age of 65. The first measures in a water system lowered mortality by half a percent compared with baseline levels. The effect on mortality came more slowly than the decline in pollution.

The measures also reduced the number of hospital admissions. Those that targeted disease-causing microorganisms reduced admissions linked to such infections. According to the Centers for Disease Control and Prevention, pathogens in drinking water cause 7 million illnesses and 600,000 emergency department visits each year.

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