Gross Alpha Radiation, Uranium and Radium in Drinking Water

Gross alpha radiation may cause health effects over time. Because gross alpha radiation loses energy rapidly and within a short distance, it does not pass through the skin. It is not a hazard outside of the body. However, the radiation can be harmful if you eat, drink or breathe in something containing gross alpha radiation.

Over a long period of time and at high levels, radium increases the risk of bone cancer and uranium increases the risk of kidney damage. There are no immediate health risks or symptoms from drinking water that contains gross alpha radiation.

Since gross alpha radiation, uranium and radium are naturally found in the Earth's crust, they can get into your drinking water if your well is drilled into or near natural rock formations that contain radioactive elements. The amount of gross alpha radiation in water varies because the Earth's crust contains varying amounts of radioactive elements. As radioactive elements decay, gross alpha radiation continues to be released into groundwater as positive ions called cations (for example, radium 226 and 228), negative ions called anions (for example, uranium), or as radiation with no charge.

You cannot see, smell or taste gross alpha radiation or radioactive elements. Testing is the only way to know if they are in your water.

The Health Department recommends testing your well or spring for gross alpha radiation and uranium every five years. You can order a gross alpha radiation screen (Kit RA) and uranium test (as part of Kit C or an individual test) from the Health Department Laboratory, or you can use another certified drinking water lab to test for radioactive elements. The radium-226/228 test is not offered at the Health Department Laboratory but can be ordered from a certified drinking water lab.

The drinking water standards for radioactive elements are: 

• Combined radium 226/228 = 5 pCi/L
• Uranium = 0.020 mg/L (milligrams per liter)
• Adjusted gross alpha = 15 pCi/L

If your unadjusted gross alpha is greater than 5 pCi/L, further calculations or testing is needed to make sure the radioactive elements in your water are below the standards. Use the Adjusted Gross Alpha Calculator to calculate radium and the adjusted gross alpha using the results for uranium and gross alpha.

The Health Department recommends treating your water:

• If your final result for uranium is more than (>) 0.020 mg/L.
• If your final result for radium is more than (>) 5 pCi/L.
• If your final result for adjusted gross alpha is more than (>) 15 pCi/L.

If your adjusted gross alpha is more than (>) 5 pCi/L, it is likely caused by radium. Consider treating for radium (for example, with a water softener), or testing for radium-226/228 to confirm the elevated adjusted gross alpha level is due to radium and not other radioactive elements.

Need help understanding your drinking water test results? Find out how to read your results

Because gross alpha radiation causes cancer, any exposure to it will increase your risk of getting cancer. If you would like to lower or eliminate your exposure, consider treating your water for gross alpha radiation, even if it is under the drinking water standard.

The Health Department also recommends testing your indoor air for radon, which may be present in areas with a higher concentration of radioactive elements. Learn more about testing your home for radon

Radioactive elements can be removed from drinking water by using one of the treatment systems listed below. There are different treatments for different elements. Your water may need to be treated for other water quality issues — such as hardness, iron, manganese and pH level — before it’s treated for radium or uranium. A water treatment professional will be able to determine which treatment system is best for your water.

• Reverse osmosis (RO): RO treatment addresses all gross alpha radiation contaminants. It uses a synthetic membrane that allows water to go through but leaves radium, uranium and other radioactive elements behind. The membrane is continually rinsed. It is usually installed under the kitchen sink (point-of-use or POU), but can also be installed as a whole house system (point-of-entry or POE). Install a system with an NSF/ANSI Standard 58 Certification. 
• Water softener: A conventional water softener (also called a cation exchange softener) can be used to reduce the level of radioactive ions with a positive charge, like radium. This treatment exchanges radium for sodium or potassium, which remains in the water. The radium is flushed away with the wastewater when the softener is cleaned. This type of treatment is typically installed as a POE system, and also will also lower the hardness of water throughout the home. These systems are most effective if the adjusted gross alpha is greater than 5 pCi/L and uranium is less than 0.01 mg/L. This will not lower the levels of uranium in the water, or reduce any radioactivity caused by uranium.
• Anion exchange: Anion exchange is a treatment like water softening but uses a different media that exchanges the negatively charged radioactive ions, like uranium for chloride. This is also typically a POE system. These systems are most effective if the adjusted gross alpha is less than 15 pCi/L and uranium is above 0.02 mg/L. This treatment method will not lower the level of radium in the water, or reduce any radioactivity caused by radium.

Re-test your drinking water for gross alpha radiation and/or uranium after any treatment system is installed to make sure levels are below the drinking water standards.

Funding is available to help you pay for water treatment or to fix your water system. Learn more about financial assistance programs and eligibility.