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1. What is Tritium?

Tritium (H-3) is a weakly radioactive isotope of the element hydrogen that occurs both naturally and during the operation of nuclear power plants. Tritium has a half-life of 12.3 years and emits a weak beta particle. The most common form of tritium is in water, since tritium and normal hydrogen react with oxygen in the same way to form water. Tritium replaces one of the stable hydrogens in the water molecule, H2O, and creates tritiated water, which is colorless and odorless.

Tritium can be found in self-luminescent devices, such as exit signs in buildings, aircraft dials, gauges, luminous paints, and wristwatches. It is also used in life science research and in studies investigating the safety of potential new drugs. Click here for more information from the EPA.

2. Does this affect Monticello’s drinking water?

The public water system operated by the City of Monticello has been unaffected by the leak at the Monticello Xcel Energy Facility. 

The source for the City of Monticello municipal water system is from five deep wells located east of State Highway 25. As part of the City’s wellhead protection plan, the areas of influence for the city’s wells and the flow path for the corresponding aquifer have been modeled.  

The area where the leak occurred is outside of this wellhead protection area and outside of the area where modeling showed our wells draw. Xcel Energy has their own monitoring wells that are separate from the City of Monticello’s water system. The Xcel system is where the contamination was detected.

We’re committed to providing information and answering any questions as more information continues to become available.

3. Is the City testing our Municipal Water System?

In March the City of Monticello submitted water samples from our municipal wells to a private vendor to test for tritium. The results confirm the city drinking water supply is safe and well below the EPA's drinking water standards for tritium levels.

City officials continue to be confident in the scientific analysis by federal and state agencies that show the tritiated water plume has not left the Xcel Energy site and has not impacted the safety of Monticello’s public water system. However, city leaders want to ensure the public feels the same confidence in their drinking water.

The tritium-related health limit established by the Environmental Protection Agency for drinking water is 20,000 pCi/L (picocuries per liter). The highest sample result from Monticello’s municipal wells was 209 pCi/L, the lowest was 33.9 pCi/L. All results were well below the EPA's tritium-related health limit. These results support state agency assertions that the plume has not migrated off-site or impacted municipal drinking water.

Tritium is a naturally occurring form of hydrogen that is produced in the upper atmosphere. According to the EPA, "Levels of naturally occurring tritium in the atmosphere produced by cosmic rays are constant." As a result, low levels of tritium are commonly found in drinking water. Tritium levels in drinking water are also commonly used in science to date the age of the water in aquifers.

With the confirmation provided by the test results, we hope the public feels reassured knowing the municipal water tested far below the risk level set by the EPA. The safety of Monticello’s residents will continue to be our number one priority. City leaders will continue to share information as it becomes available.

4. Who can I contact for more information about the leak at Xcel?

We understand the notification from Xcel Energy and the State of Minnesota may cause public concern. We encourage members of the public to use the resources and contact button on Xcel Energy's website for questions about the leak and the plant. While our local leaders continue to monitor the situation, the response and containment of the leak are being managed by agencies of the State of Minnesota and Xcel Energy. 

The public water system operated by the City of Monticello has been unaffected by the leak at Xcel. We’re committed to providing information and answering any questions as more information continues to become available.

If there is any impact to our drinking water supply or infrastructure, we will immediately notify the public with assistance from coordinating state agencies. For immediate text and email alerts in the event of future public safety messages, residents can subscribe to our City Alerts Program.

Additional Contact Information

• For residents that have concerns about private wells, contact Jennifer Weier at MN Department of Health (Jennifer.weier@state.mn.us or 651-201-3658) 
• For residents with general questions, contact Steve Mikkelson at MPCA (stephen.mikkelson@state.mn.us or 218-316-3887)

5. How did the leak at the Xcel Monticello Plant happen?

Xcel Energy identified the source of the leak as a water pipe running between two buildings. To contain the leak, the facility is diverting the water to an in-plant water treatment system, preventing additional water from leaving the plant, and will install a permanent solution in the spring of 2023. A thorough inspection was conducted of all piping in all locations where a leak could occur, to verify that no other area of the facility was facing this issue. The company will also be examining the one pipe that did leak in a laboratory to better understand why this happened. These findings will help Xcel Energy ensure it does not encounter the same issue moving forward.

6. How is the leak at Xcel Monticello Plant being managed?

Xcel Energy notified the Nuclear Regulatory Commission (NRC) as well as the state when the leak was confirmed. The company has since coordinated regularly with regulators as the company has been pumping, storing, treating and reusing the leaked water.

Xcel Energy has indicated that ongoing monitoring from over two dozen on-site monitoring wells confirms that the leaked water is fully contained on-site and has not been detected beyond the facility or in any local drinking water. State agencies continue to monitor Xcel Energy’s remediation work to ensure the continued safety of the local community and surrounding environment.

The company has constructed new monitoring and recovery wells and has increased the frequency of measurements from its network of over two-dozen groundwater monitoring wells to enhance its monitoring and recovery efforts. Large storage tanks are also likely to be constructed on-site to store recovered water until it can be treated and reused.

The federal and state regulating agencies determine the appropriate governmental responses to incidents at the Xcel nuclear plant, including any emergency response, remedial actions and public information and media releases. If there is any impact to our drinking water supply or infrastructure, we will immediately notify the public with assistance from these agencies. For now, we will continue to advocate for our community and participate in the response as appropriate at the city-level.

7. How do I test my private well for Tritium?

According to the Minnesota Department of Health (MDH) there is no evidence at this time to indicate impacts or risk to private wells in the vicinity of the plant. The plume has not migrated off the site. There are no private wells located in the direction of groundwater flow between the plume and the Mississippi River. MDH does not have plans to test private wells at this time but will continue to monitor water sources and evaluate the situation.

If you would like to test your private well water for tritium

As a private well owner, you are responsible for regularly testing the water you use for cooking and drinking to make sure it is safe. MDH recommends that you test your well water for several contaminants. While MDH has not issued a recommendation for private well owners to test for tritium in response to the recent release at the Monticello plant, we want to make sure well owners have information about the issue and considerations.

• Learn more about general testing recommendations here: Well Testing, Results, and Options.
• MDH has no evidence at this time to indicate impacts or risk to private wells in the vicinity of the plant. The plume has not migrated off the site. If you would like information about well testing and tritium, please see Testing Your Private Well Water for Tritium (PDF).

8. Where can I find additional resources?

For more information click on the following links:

• Xcel Energy: Press Release, March 16, 2023
• Minnesota Pollution Control Agency: Press Release, March 16, 2023
• Xcel Energy: Press Release, March 22, 2023
• Xcel Energy: Monticello Community Update: March 31, 2023
• Xcel Energy: Monticello Resource Page
• Minnesota Department of Health: Resource Page - Monticello Tritium Leak
• Minnesota Department of Health: Testing Your Private Well for Tritium
• U.S. Dept of Health: Xcel Energy Tritium Leak Resources
• U.S. Nuclear Regulatory Commission: Groundwater Contamination (Tritium) at Nuclear Plants
• U.S. Nuclear Regulatory Commission: Backgrounder on Tritium, Radiation Protection Limits, and Drinking Water Standards

9. What are the next steps?

The Minnesota Pollution Control Agency (MPCA) is leading and coordinating the State of Minnesota’s oversight of the Xcel Monticello Plant tritium release. The MPCA, along with the Minnesota Department of Health (MDH) and Minnesota Department of Natural Resources (DNR), continues to review and assess Xcel’s actions to contain and prevent tritiated groundwater from discharging into the Mississippi River.

Each agency has specific roles. The MPCA provides input on the storage and management of tritiated water on the Xcel site and expediates any permit requests. MDH assesses the tritium release’s risk to human health and provides public updates regarding the risk. The DNR assesses ecological risks due to tritium concentrations and prepared to conduct fish and wildlife sampling, if needed.

Next Steps 

The State continues to monitor and oversee Xcel’s activities to contain the tritium release and assess any potential impacts of tritium discharging to the Mississippi River. In addition, the State is reviewing permitting requests for storing the tritium groundwater. The MPCA and other state agencies will continue to provide timely public updates as significant developments in the monitoring and cleanup occur.