Free Testing Reveals What Colorado Well Owners Were Never Told: Their Water Contains Uranium

Hundreds of rural Colorado residents are drinking tap water contaminated with uranium and other heavy metals after decades of groundwater depletion concentrated naturally occurring minerals to dangerous levels. According to an investigation by Inside Climate News, families in El Paso and Elbert counties are now learning their private wells contain uranium at concentrations exceeding federal drinking water standards, sometimes by several times the legal limit.

The contamination stems from the San Isabel aquifer, which has dropped more than 100 feet in some areas since the 1980s. As water levels fall, the remaining groundwater becomes increasingly concentrated with minerals that were once diluted across a larger volume.

How Falling Water Tables Concentrate Uranium

Uranium occurs naturally in the bedrock underlying much of Colorado's eastern plains. Under normal aquifer conditions, these minerals dissolve into groundwater at low concentrations that pose minimal health risk. But when an aquifer is pumped faster than it recharges, the remaining water carries a higher proportion of dissolved solids.

"We've been drinking this water for 15 years," said Sarah Lindstrom, a resident of Elbert County whose well tested at 47 micrograms per liter of uranium. The EPA's maximum contaminant level for uranium is 30 micrograms per liter.

Unlike municipal water systems, which must test regularly and notify customers of violations, private well owners in Colorado are not required to test their water. Most families in the affected area had no idea their water quality had changed until a local advocacy group organized free testing in 2025.

A Patchwork of Contamination Across the Front Range

The uranium contamination is not evenly distributed. Some wells test clean while neighboring properties show levels three or four times the federal limit. Arsenic, another naturally occurring heavy metal, has also appeared in elevated concentrations in several tested wells.

According to state geological surveys, the San Isabel aquifer supplies drinking water to an estimated 3,200 households across the region. Of the 340 wells tested so far, 89 exceeded the federal uranium standard.

The affected communities sit in a regulatory gap. They are too rural to connect to municipal water systems and too dispersed to justify the cost of building new infrastructure. Many residents purchased their properties specifically for the independence of well water, only to discover that independence comes with risks utilities would have been required to monitor.

Colorado Offers Bottled Water While Families Wait for Treatment Funds

The Colorado Department of Public Health and Environment has offered affected households bottled water and connected some families with emergency funds for treatment systems. But officials acknowledge there is no mechanism to restore the aquifer or guarantee safe water for residents who cannot afford filtration.

"We can provide guidance on treatment options, but the responsibility ultimately falls on the well owner," said Marcus Chen, a spokesperson for the department. The state has allocated $2.1 million for a voluntary well-testing expansion, though the program will not begin accepting applications until late 2026.

For families already dealing with contamination, the wait is untenable. Reverse osmosis systems capable of removing uranium cost $2,000 to $5,000 installed, not including ongoing filter replacement. Whole-house treatment systems can exceed $10,000.

The Aquifer Problem Beyond Colorado

Colorado's situation reflects a broader pattern across the American West. The U.S. Geological Survey has documented similar aquifer declines in Kansas, Nebraska, and Texas, where agricultural pumping has outpaced natural recharge for decades. As climate change intensifies drought cycles, the gap between extraction and replenishment widens.

Unlike surface water contamination, which can be traced to a specific discharge point, aquifer depletion is cumulative. By the time well owners notice their water quality has changed, the underlying problem may have been building for years.

What This Means for You

If you're in Colorado's Front Range region:

• Request a well water test through the state's voluntary testing program or a certified private lab. Test specifically for uranium, arsenic, and total dissolved solids.
• If your well tests above 30 micrograms per liter for uranium, switch to bottled water for drinking and cooking until you install treatment.

For general preparedness:

• Well owners in any region with declining water tables should test annually for heavy metals, not just bacteria. Our guide on how to test water quality at home covers the process.
• If you rely on a private well, budget for treatment equipment before contamination appears. Reactive purchases after a crisis cost more and take longer to install.

What Removes Uranium From Well Water

Uranium is a dissolved mineral, which means standard sediment filters and basic carbon cartridges will not remove it. The contaminant passes through any filter that is not designed for dissolved heavy metals. Effective treatment requires either reverse osmosis, which forces water through a membrane that blocks particles at the molecular level, or ion exchange systems designed specifically for radionuclides.

For households on well water, a point-of-use reverse osmosis system installed at the kitchen sink addresses drinking and cooking water at a lower cost than whole-house treatment. Systems certified to NSF/ANSI 58 are independently verified to reduce uranium along with other heavy metals. Our review of the best well water filtration systems covers whole-house options for those who need treatment at every tap, and our under-sink filter guide compares systems for point-of-use applications.