Radon in Well Water

The NC Radiation Protection Section advises homeowners with private wells to follow the recommendations set forth by the North Carolina Radon-in-Water Advisory Committee.
View the recommendations

These recommendations, found on page 5 of the final report, are as follows: 

• Private wells with radon concentrations at or above 10,000 pCi/L: Treatment of water should be considered in conjunction with a radon in air mitigation system. 
• Private wells with radon concentrations between 4,000 and 10,000 pCi/L: Treatment of water should be considered optional. 

This recommendation is made recognizing that the radon-concentration in water is to help determine whether water is a significant contributor to existing indoor air radon levels. Inhalation of radon in air poses a greater health risk than ingestion of radon through water. The recommendation seeks to address the combined sources of radon from soil gas and radon released from water. The goal is to limit the combined radon exposure in the home to no more than the Environmental Protection Agency (EPA) recommended level of 4 pCi/L. As a general rule, 10,000 pCi/L radon in water will contribute 1 pCi/L radon to the air in the home. 

Radon can be transported into a home through the plumbing of homes receiving water from a well. The concern with high levels of radon in water is that it can elevate the levels of radon in the home’s air. When testing water for radon, it is important to know that the data result, the number value, is viewed differently.

The NC Radon Program recommends that you first test your air for elevated radon levels. Should your radon test for the air indicated an elevated radon level, testing for radon in your well-water maybe helpful to determine if the home’s plumbing is the pathway in which the radon is entering your home.

The risk of radon in drinking water has been estimated by the EPA to cause 168 cancer deaths per year in the United States. The majority of these deaths (about 89%) are caused by breathing in radon that has gassed out of the water while washing dishes or showering, which leads to lung cancer. Overall, lung cancer deaths from airborne radon are estimated to be about 20,000 per year in the U.S. For this reason, it is always recommended that homeowners test for airborne radon in their home, as this presents the greater risk. 

Testing for radon in air or water is easy and affordable. There are a number of radon test kits available online or in your local home improvement store for $20 or less. 

Exposure to radionuclides has the potential to harm your health. Contact with any hazardous substances can cause health effects. The occurrence and nature of the effects depend on how much, how long and how one comes into contact with the substance.

What are radionuclides?

Radionuclides are elements that give off radiation as they break down. In nature, radionuclides can be found in rocks and soil and can get into ground water and into wells.

Gross alpha: Are alpha particles that can travel short distances and cannot travel through your skin.

Gross beta: Are beta particles that can penetrate through your skin, but are unable to travel through your body.

Both alpha and beta particles can be released as a product of radioactive decay.

Uranium: Natural uranium is a mixture of three isotopes: 234U, 235U, and 238U. The most common isotope is 238U which make up over 99% of natural uranium. 238U is the least radioactive of the three isotopes.

Radium226/228: Radium is formed when uranium and thorium break down in the environment. Uranium and thorium are found in small amounts in most rocks and soil.

Approximately 80% of exposure to radioactivity is natural and the rest comes from man-made sources. For example, exposure can occur from naturally occurring radiation from the emission of radon gas from rocks and soil, and radioactive elements in groundwater.

How could I be exposed to radionuclides

Individuals can be exposed to radionuclides by ingestion (eating or drinking) and inhalation (breathing). Dermal (skin) exposures to radionuclides are not considered to significantly contribute to increased health risks.

Certain rock types which have naturally occurring trace amounts of mildly radioactive* elements that serve as the "parent" to other radioactive contaminants ("daughter products"). These radioactive contaminants, depending on their chemical properties, may accumulate in drinking water sources at levels of concern.

*Mildly radioactive elements are defined as elements with very long half-lives.

How do radionuclides get into well water?

Radionuclides can get into ground water and into wells if you live in an area where they are naturally present in the rocks and soil. 

What areas of the state are more likely to have high levels of radionuclides in groundwater?

There are limited data on the occurrence of radionuclides in North Carolina. We do know that these elements are associated with certain types of rock formations deep underground. The following map shows areas that are more likely to have elevated radon in groundwater based on the location of these rock formations. Radon co-exists with uranium, radium and other radionuclides, so this map also indicates where other radionuclides might be elevated in groundwater. Areas in or around the colored portions of this map may be impacted by radionuclides.

Messier, K. P., Campbell, T., Bradley, P. J., & Serre, M. L. (2015). Estimation of groundwater Radon in North Carolina using land use regression and Bayesian maximum entropy. Environmental science & technology, 49(16), 9817-9825.

I live in an area of concern based on the map. Do I have radionuclides in my well? 

The presence of radionuclides in groundwater varies from neighbor to neighbor. You cannot smell, taste or see any of these contaminants. The only way to know is to get your well water tested.

I do not live in an area of concern based on the map. Should I be concerned about my well water? 

The presence of radionuclides in groundwater varies from neighbor to neighbor. These contaminants may even be present in areas that are not generally predicted to have higher levels based on the underlying rock formations. The only way to know is to get your well water tested.

I don’t have a private well. Should I be concerned?

If you receive water from a public water supply (community wells, county systems or municipal systems) your water is regulated by the NC Department of Environmental Quality to ensure your water does not exceed maximum contaminant levels for radionuclides. However, public water supply users may still be at risk from indoor radon in air that comes from other sources besides water. 

Do I need to get my home tested for radon in the air?

Yes. The North Carolina Radiation Protection Section recommends that all homes and buildings in North Carolina are tested for radon. Radon is a gas that can enter your home through your floors/foundation and from radon dissolved in groundwater. Testing for radon is important because breathing radon in indoor air can cause lung cancer. 

What are the health effects of radionuclides exposure?

The health effects of radionuclides depend on which radionuclides you are exposed to. Generally, drinking water with elevate radionuclides have been linked to adverse health effects and cancer. 

• Radon exposure has been linked to stomach cancer.
• Uranium exposure has been linked to kidney damage and cancer. 
• Radium exposure has been linked to bone cancer. 

In addition, breathing air with elevated radon is the second leading cause of lung cancer, after cigarette smoke. If contaminant concentrations in your well water are elevated, you can contact the Occupational and Environmental Epidemiology Branch (OEEB) in the North Carolina Department of Health and Human Services at (919)-707-5900. The OEEB can answer questions regarding potential health effects and possible actions to reduce the levels of the contaminant(s) in your well water. You can find additional information on radionuclides, radon and uranium at the following links:

Radionuclides: https://epi.dph.ncdhhs.gov/oee/docs/Radionuclides_WellWaterFactSt.pdf

Radon: https://epi.dph.ncdhhs.gov/oee/docs/RadonandLungCancerFactsheet.pdf

Uranium: https://epi.dph.ncdhhs.gov/oee/docs/Uranium_WellWaterFactSt.pdf

How can I limit or prevent my exposure to radionuclides?

1. Avoid radionuclides exposure sources.
2. Test your drinking water for radionuclides. If elevated, consider installing a reverse osmosis treatment system to remove radionuclides from the water.
3. Test your home for radon. If your test results indicate elevated radon levels, consider installing a radon mitigation system.
4. If you work around radionuclides, use proper personal protective equipment while working, and wash clothes and/or skin that comes in contact with radionuclides.

Is there a medical test to show if I have been exposed to radionuclides?

There are many ways to see if you have radioactive material in your body. Radioactive material can be measured in your blood, feces, saliva, urine, and throughout your entire body by specialized instruments. The instrument is chosen based on the type of radiation that is to be measured. Consult with your healthcare provider to determine if such a test is recommended and where to receive the appropriate test. Also, these tests cannot tell the level of exposure, nor can they be used to predict whether you will develop harmful health effects.

If I want to get my well tested where can I go?

If you live in Wake County, contact the Wake County Environmental Health Department at 919-893-WELL or visit wakegov.com/wells. 

If you live in Franklin County, contact Franklin County Environmental Health Department at 919-496-8100. 

Are there treatment options for radionuclides in my well water?

There are treatment systems that can get rid of radionuclides in water; the type of system depends on the kind of radionuclide.

How much will it cost to fix the problem if tests find radionuclides in my well water?

If the testing indicates problems, it could cost anywhere from $1,000 to $15,000 to install the treatment system. The cost will depend on what the testing indicates and what approach you want to take to fixing it. 

To discuss options, you can contact the Occupational and Environmental Epidemiology Branch (OEEB) in the North Carolina Department of Health and Human Services at (919)-707-5900. The OEEB can provide guidance and recommendations for treatment options to reduce contaminants detected in your well water.

What should I do if I think my health has been affected by contaminants identified in my results?

If you think your health has been affected by contaminant(s) identified in your well water, talk with your doctor about your specific concerns and show them your well water results. 

Additional Information

Call the N.C. Department of Health and Human Services, Division of Public Health at (919) 707-5900 for additional information.

References

• Agency for Toxic Substances & Disease Registry (ATSDR). ToxFAQs for Ionizing Radiation. September 1999. Available at: http://www.atsdr.cdc.gov/toxfaqs/tfacts149.pdf
• Agency for Toxic Substances & Disease Registry (ATSDR). ToxFAQs for Uranium. February 2013. Available at: https://www.atsdr.cdc.gov/toxfaqs/tfacts150.pdf