Thousands of public water systems across the United States still do not know where lead pipes are located, according to a recent analysis by the Associated Press using data from the U.S. Environmental Protection Agency (EPA). More than 1,300 water systems have been cited for failing to meet a deadline set for October 2024 to submit an inventory of water lines that could be leaching lead into drinking water. About 6,300 water systems serving 3.8 million Americans have not submitted the required list of lead service lines in use. These inventories are crucial because they help cities replace all lead pipes by a 10-year deadline set for 2027. In Dunkirk, New York, Kathryn Pilgrim, a special education teacher, bought a century-old home and replaced pipes she suspected might contain lead. Despite these efforts, she still cannot be certain her tap water is free of lead because she doesn’t know the material of the pipe under her front yard. Dunkirk, which supplies water to about 5,000 homes and businesses, is nearly two years behind schedule on creating an inventory that would provide such information. Officials in the city did not respond to requests for comment. Lead pipes are common in many older communities, including New York. In Buffalo, 45% of service lines are made of lead, the third-highest rate among major U.S. cities. Neighboring Fredonia reported 28% lead service lines. Lead is a toxic metal that can harm children’s development, lower IQ scores, and raise blood pressure in adults. The EPA estimates that about 4 million homes and businesses are still connected to water utilities via lead pipes. The EPA has highlighted its focus on lead pipes as a significant environmental achievement. Since President Donald Trump returned to office, about three-quarters of the EPA’s drinking water enforcement orders have been related to missing inventories. Most of these systems are small, with 84% serving fewer than 500 people. The EPA said it turned to enforcement only after attempts to help these systems comply failed. Utilities need these inventories to prepare for a 2027 deadline requiring most drinking water providers to replace lead lines within 10 years. This deadline was set by the Biden administration but has been defended by the Trump administration in court. Rob Hayes of Environmental Advocates of New York noted that this regulation is rare in being supported by the Trump administration. Creating complete inventories is challenging. About 3,500 water systems reported they do not know the material of their service lines. One in five service lines nationwide are reported to have unknown materials. Many utilities are working to identify these unknown pipes by next year, when they must start replacing them. In Chicago, which has the most lead lines in the country, crews are working block-by-block to dig up pipes branching off from the main line. The city still doesn’t know the material of close to one in 10 service lines. Lead pipes have been used in public water systems since the late 1800s and were common until the 1950s. At the time, lead was preferred because it resisted corrosion, and many of these lines remain in use today. Chicago advises residents with unknown lines to assume they are made of lead if their building predates 1986, when lead was banned under the U.S. Safe Drinking Water Act. Records of installations were often lost, incomplete, or difficult to read. Lapses in recordkeeping have made it difficult for some utilities to complete their inventories. Joshua Klainberg of the New York League of Conservation Voters said not submitting an inventory is “unforgivable” because even incomplete information can help residents take precautions, such as running the tap, using high-quality filters, and cooking only with cold water. Starting in 2027, utilities without complete inventories will face stiffer consequences. They will be required to replace 10% of lead pipes each year with copper or plastic pipes. Lines made of unknown materials will be included in this target. Each replacement is costly, typically ranging from $8,000 to $15,000. In Chicago, the city is seeking every available dollar from federal and state governments to fund these replacements. Most funding for identifying and replacing lead pipes comes from the 2021 bipartisan infrastructure law, with states distributing the funds. This is the final year of dedicated federal funding for lead projects, though previously allocated money will continue to be used. Water systems without an inventory will fall further behind as national efforts shift toward replacements. Hayes warned that without proper inventories, it will be difficult to gather the resources and coordination needed to replace the pipes.