The distribution system piping in U.S. public water systems that rely on non-disinfected well water or “ground water” may be a largely unrecognized cause of up to 1.1 million annual cases of acute gastrointestinal illness (AGI), involving nausea, vomiting and diarrhea, scientists are reporting. Their study in ACS’ journal Environmental Science & Technology concludes that such illnesses may become more of a problem as much of the nation’s drinking water supply system continues to age and deteriorate.

Frank J. Loge, Mark A. Borchardt and colleagues explain that more than 100 million people in the U.S. rely on water piped into homes, schools and businesses from public water systems that get their water from wells, rather than lakes, rivers and other above-ground sources. Much of that water either is not disinfected at all or is not adequately disinfected to kill disease-causing viruses.

Their new analysis of the risk of AGI from these well-based water supply systems concluded that contamination of distribution system piping may be responsible for 470,000 to 1.1 million cases of AGI every year. They also warn that the incidence of AGI from public water systems is likely to rise in coming years: “So far insufficient financial investments have been made to improve water infrastructure, and small systems are particularly at risk for lack of funds and personnel. As most of the national water distribution infrastructure is reaching the end of its design life in the coming decades, the frequency and health impacts of distribution system deficiencies will likely worsen.”