Radon in Drinking Water

Radon is a naturally occurring radioactive gas. Radon comes from the decay of uranium, which is a radioactive element found naturally in the earth’s crust. Over billions of years, uranium decays into radium, and eventually, radon.

Well water that contains radon may increase the level of radon in a home. Activities like taking showers, doing laundry, or running the dishwasher can release radon into the air.

Health Concerns: Is radon harmful to my health?

There are no known health effects from brief exposure to radon. However, over longer periods of time, breathing air with too much radon increases your risk of lung cancer.

Over a lifetime, swallowing radon in water also poses a risk of stomach cancer. The major danger posed by radon in water is the risk of lung cancer when radon escapes from the water and is breathed in.

If you smoke and your home has high levels of radon, your risk of getting lung cancer is especially high. The Environmental Protection Agency (EPA) estimates that 86% of radon-related lung-cancer deaths occur among current or former smokers. Learn more about radon, smoking and lung cancer

Testing: How do I know if radon is in my water?

You cannot see, smell or taste radon. Testing is the only way to know if radon is in your drinking water.

The Health Department has set an advisory level for radon in water of 4,000 pCi/L (picocuries per liter) and recommends the following:

  • If the result of the radon in water test is less than 4,000 pCi/L, you do not need to treat your water, but test your water again in five years.
  • If your radon in water result is at or above 4,000 pCi/L, consider treating your water.
  • If you haven't already, test your home for radon in air. Breathing radon in air poses more of a health risk than drinking radon in water.
Because radon concentrations in well water can vary throughout the year, it can be beneficial to test more than once at different times of the year. Order a test kit for radon in water
About 10,000 pCi/L of radon in water will increase the radon level in air by 1.0 pCi/L. If you have tested both your indoor air and your water for radon, using the Radon Contribution Calculator may help you estimate how much of the radon in air is due to radon in the water supply and how much is due to air entering the home through the foundation. Learn more about radon in air
Treatment Options: Can I remove or lower the levels of radon in my water?
Radon can be removed from drinking water. There are two types of water treatments systems that can be installed.

Aeration System

An aeration system uses a fan to reduce radon in water. This system mixes your water with air inside a tank and then vents the air and radon outdoors, away from the house.

Granular Activated Carbon (GAC)

This filtration system uses a charcoal filter to remove the radon from the water. The Health Department discourages the use of GAC systems to remove radon because the radon collected on the filter can pose a radiological hazard to both the homeowner and the technicians who service the system.