Princeton, Iowa sits on the banks of the Mississippi River with roughly 1,000 residents and, until recently, a single aging well drilled in 1963 as its only source of drinking water. After years without a backup, the town invested nearly $800,000 to drill a new well and build a water tower — a solution that was supposed to finally give the community a safety net.
The new well has been shut down since September 2024. Water samples showed nitrate levels above the federal safety limit, making it undrinkable. Nearly two years later, Princeton’s 350 households are still relying entirely on that six-decade-old pipe in the ground, and city officials are running out of affordable paths forward.
A $800,000 Investment That Cannot Be Used
The new well’s troubles began before anyone tested the water. In late 2022, an overly powerful pump caused eight months of water main breaks across town — switching to a smaller motor resolved that, but then exposed something worse.
Princeton had capped its previous backup well in 2009 after years of state violations for high nitrate levels. The new well and water tower, built to replace it, cost nearly $800,000, funded in part by a roughly $400,000 USDA loan the city expects to repay through 2040.
In September 2024, state regulators notified Princeton that water from the new well tested at 12.1 mg/L of nitrate, above the EPA’s maximum contaminant level of 10 mg/L. The city shut it down immediately. Nitrate concentrations peaked at around 16 mg/L in spring 2025, and not a single sample since has fallen within the legal range.
That leaves the town’s 350 households and businesses entirely dependent on the original 1963 well. “We have 1,000 people that need water, potable water,” said Chris Rindler, the city’s public works foreman. “To not give them that reliable backup — I don’t think that’s an option.”
Deep Wells Were Supposed to Be Safe from Farm Pollution
All three of Princeton’s wells — two decommissioned, one still running — reach nearly 450 feet underground, drawing from the Silurian-Devonian aquifer through layers of clay and fractured limestone. At that depth, contamination from surface agriculture is not supposed to happen.
Nitrate runoff from fertilizer and manure is a well-documented problem in Iowa’s surface waters. Deep aquifers, though, were long considered naturally shielded from that chemical footprint. Ryan Clark, associate state geologist at the Iowa Geological Survey, says the reality is more complicated. The interplay between surface pollution and deep groundwater reserves remains poorly understood.
The evidence suggests Princeton’s problem is not isolated. Nitrate levels in Silurian wells serving Cedar Rapids were already approaching the EPA limit back in 1999, and elevated readings have since turned up in Silurian wells as far north as Green Bay, Wisconsin. “Almost all of the Silurian aquifer beneath Eastern Iowa is impacted by nitrate to some degree,” Clark said. “It’s a much bigger picture.”
Limiting Fertilizer Near the Well Has Barely Moved the Needle
In spring 2025, Princeton took direct action. On the advice of the Iowa Rural Water Association, the city leased roughly 25 acres of farmland surrounding the contaminated well from three landowners, paying $300 per acre per year not to apply fertilizer. The arrangement costs the city just under $8,000 annually.
None of the three landowners was enthusiastic, but all complied. Mayor Travis Volrath acknowledged the difficult position that creates for farmers. “I don’t think nobody wants to be blamed for the problem,” he said.
After a year of the program, nitrate levels have dropped by only about 1 mg/L — the well is still averaging more than 5 mg/L above the legal limit. “The data shows that we haven’t moved the needle much,” Volrath said. Clark is not surprised. The contamination footprint is almost certainly far larger than any wellhead protection zone can address, and Volrath himself now questions whether local agriculture is truly the primary source.
A Cracked Casing Would Be the Best-Case Scenario
City officials are holding onto one more hopeful explanation: a crack in the well casing. That tube extends several hundred feet into the ground and is designed to block shallower groundwater from entering the well. A fracture could allow “legacy nitrate” — nitrogen accumulated in the soil over decades of intensive farming — to infiltrate the water supply more rapidly.
If that is the cause, it would at least be fixable. A Princeton city council member said at a May 2026 meeting that finding a crack would be “the best possible case scenario.” The city submitted an application to the state DNR for a $10,000 grant to fund an exploratory study to locate any such damage.
No crack, though, would mean contamination is entering through fractures in the limestone bedrock itself — a scenario that makes remediation significantly more complex and expensive. Drilling deeper is not a guaranteed solution either, since tapping a lower aquifer could expose it to the same contamination already affecting the Silurian.
Princeton’s Dilemma Mirrors a Statewide Water Crisis
Princeton is not an outlier. Nitrate violations were the leading cause of health-based infractions among Iowa public water supplies in 2024, according to the state DNR’s annual compliance report. Several other towns have approached both the Iowa Rural Water Association and the Iowa Geological Survey with nearly identical deep-well nitrate problems in recent years.
The most straightforward technical fix — a reverse osmosis filtration system — would cost Princeton more than $1 million. That is money the town simply does not have. Borrowing more, stacked on top of the USDA loan already on the books, is a path Volrath describes as a last resort.
Consolidation with a larger utility is another option, though a politically difficult one. In 2021, the Princeton city council rejected a $2 million buyout offer from American Water, the nation’s largest regulated water utility, because the company required infrastructure upgrades that exceeded the offer’s value. The conversation has resurfaced, but no deal is in place.
Researchers are still working to determine whether the nitrate in Princeton’s water comes from synthetic fertilizer, livestock manure, or some combination of both. Initial isotope tests are inconclusive. The results of that analysis, combined with the outcome of the casing inspection grant, will likely determine what options the city pursues next — and how much it will cost a small river town that has already spent $800,000 on a well it cannot use.