PRINCETON — In September 2024, the city of Princeton, Iowa, shut down a newly built $800,000 well after tests showed its water contained 12.1 milligrams per liter of nitrate, exceeding the Environmental Protection Agency’s legal limit of 10 milligrams per liter. The closure left the town of approximately 1,000 residents dependent on a single well drilled in 1963.
Princeton invested nearly $800,000 to drill the new well and construct an accompanying water tower to serve as a backup water source. The city had operated without a secondary well since capping a 40-year-old auxiliary well in 2009 due to repeated nitrate violations. An overly powerful pump caused eight months of water main breaks in late 2022, further straining the aging system.
Since the new well’s shutdown, none of its water samples have met federal nitrate standards. Nitrate levels peaked at approximately 16 milligrams per liter in spring 2025 and have since declined by only 1 milligram per liter, despite the city leasing 25 acres of surrounding farmland to restrict fertilizer use. Princeton pays three landowners $300 per acre annually—totaling just under $8,000 per year—to maintain a wellhead protection zone.
“I would say the data shows that we haven’t moved the needle much. It has gently trended down, but not far enough to matter,” Mayor Travis Volrath said. He added, “I didn’t put the well there, they didn’t put the well there, but the fact is, it’s there now. We have to deal with it, and, you know, I don’t think nobody wants to be blamed for the problem.”
Chris Rindler, Princeton’s public works foreman, emphasized the need for reliable water access. “We have 1,000 people that need water, potable water. And to not give them that reliable backup, well, I don’t think that’s an option,” he said.
All three of Princeton’s wells—two decommissioned and one active—extend nearly 450 feet into the Silurian-Devonian aquifer. Ryan Clark, associate state geologist at the Iowa Geological Survey, noted that high nitrate levels are typically rare in such deep aquifers. He said elevated readings have appeared in similar wells as far north as Green Bay, Wisconsin, and referenced a 1999 U.S. Geological Survey warning about rising nitrate levels in Silurian aquifer wells near Cedar Rapids. “It’s a much bigger picture,” Clark said. Princeton submitted an application in May to the Iowa Department of Natural Resources for a $10,000 grant to fund an exploratory study to determine whether a crack in the well’s casing is allowing surface nitrogen or legacy nitrate to contaminate the supply.