Residents of a Chicago neighborhood where drinking water flows through an estimated 400,000 lead service lines — more than any other utility in the United States — face a compliance record marked by 19 violations over five years, including an active health-based violation still unresolved as of April 2026, according to data from the EPA's Safe Drinking Water Information System.
The ZIP code in question, 60608, covers Pilsen and the Lower West Side on Chicago's south side. The utility responsible, the Chicago Department of Water Management (EPA ID IL0316000), recorded a lead 90th-percentile level of 9.3 parts per billion in its most recent Lead and Copper Rule testing cycle. The EPA's current action level is 15 ppb — a threshold that, while 60608's figure falls below it, many researchers have argued does not adequately reflect the evidence on low-level lead exposure and developmental harm in children.
Of the 19 violations recorded in the five-year window, 18 were non-health-based — monitoring and reporting failures — and one was a health-based violation that remains open.
Chicago's critical gap is not at the treatment plant. It is underground, in the roughly 400,000 lead service lines connecting the city's water mains to individual homes and apartment buildings — lines that the city itself has acknowledged represent the largest inventory of lead pipes of any utility in the country. Lead enters drinking water not as a treatment plant failure but through corrosion of those lines and of lead-containing household plumbing, a process that the EPA's Lead and Copper Rule has regulated since 1991.
The 2021 Lead and Copper Rule Revisions set a goal of replacing all lead service lines within 10 years, though utilities with larger inventories, including Chicago, were given extended compliance pathways. Illinois law separately requires utilities to develop replacement plans. But the pace of actual replacement has remained well below what the city's own inventory would require to meet federal timelines. The city had previously conducted a replacement program that removed only the utility-side portion of the service line — a practice that researchers subsequently found could temporarily spike lead levels at the tap rather than reduce them. That program was eventually halted.
The housing age signal in 60608 is pronounced. The federal Safe Drinking Water Act amendments of 1986 banned the installation of lead pipes and lead solder in new construction; housing built before that year represents the primary exposure pathway through in-home plumbing, even after utility-side lines are replaced. In neighborhoods where both the service line and the interior plumbing are lead-containing, the cumulative exposure potential at the tap can be substantially higher than either pathway alone.
Advocates in communities like Pilsen — a predominantly Latino neighborhood with a high concentration of older housing stock — have pushed for whole-line replacement and for the city to cover costs for property owners who could not afford to replace the private-side portion themselves. Chicago has received federal infrastructure funding through the Bipartisan Infrastructure Law, which included $15 billion nationally for lead service line replacement. But advocates and city council members representing south and west side wards have continued to press for accountability on timelines, noting that replacement rates in wealthier North Side neighborhoods have historically outpaced those in communities where lead exposure risk tends to be highest, as WBEZ and the Chicago Tribune have reported.
The Chicago Department of Water Management has maintained that its corrosion control treatment — a phosphate coating applied to slow the rate at which pipes leach into the water — is functioning as designed. But researchers who have studied corrosion control in large lead-pipe systems have noted that the effectiveness of phosphate treatment can vary substantially by neighborhood depending on pipe age, pipe condition, and stagnation time in buildings with lower water turnover.
Residents in neighborhoods like 60608 who want to understand the full picture of their water compliance record — not just the headline 90th-percentile result but the violation count, the data source, and the regulatory framework behind those numbers — can look up their ZIP code at ZipCheckup, which draws directly from EPA SDWIS and updates its records as the federal database is refreshed.
The active health-based violation in Chicago's federal record, as of the April 2026 data verification, reflects an ongoing compliance matter rather than a closed enforcement action. What it does not capture, on its own, is the physical reality that hundreds of thousands of lead pipes remain in the ground across this city — and that in ZIP codes like 60608, the timeline for removing them is measured not in months but in years.