O ne in twenty tap water tests performed for thousands of Chicago residents found lead, a neurotoxin, at or above US government limits, according to a Guardian analysis of a City of Chicago data trove.
This means that out of the 24,000 tests, approximately 1,000 homes had lead exceeding federal standards. Experts and locals say these results raise broader concerns, because there are an estimated 400,000 lead pipes supplying water to homes in the city, and the vast majority were not tested as part of the program.
The Guardian worked with water engineer Elin Betanzo – who helped uncover the Flint water crisis that resulted in many, mostly Black residents being poisoned by lead in the Michigan city – to review the results of water tests conducted for Chicago residents between 2016 and 2021. Chicago itself has never released an analysis of the results.
The analysis found that nine of the top 10 zip codes with the largest percentages of high test results were neighborhoods with majorities of Black and Hispanic residents, and there were dozens of homes with shockingly high lead levels. One home, in the majority-Black neighborhood of South Chicago, had lead levels 1,100 parts per billion (ppb) – 73 times the Environmental Protection Agency (EPA) limit of 15ppb.