Environmental Tests : Radon In Water

How Does Radon get into Well Water?

As well water makes its way through the aquifer it can be contaminated by radon existing in the soil/rock. Radon in well water can contribute to the indoor air levels of radon gas in your home by releasing radon into the air as water flows into sinks, tubs, and appliances. High levels of radon in well water will off-gas radon into the air when showering, bathing, or washing clothes. There is no correlation between radon that exists in air and radon in water. Consequently, if radon concerns you, both should be tested.

While the average concentration of radon in U.S. groundwater is below 1,000 pCi/L, levels in groundwater have been found above 1,000,000 pCi/L. The highest amounts have been found in the Northeast. Private wells tested in Connecticut indicate an average radon level of about 3,000 pCi/L.

How Do I Test for Radon in Water?

Since radon in water levels can vary, The State of CT Department of Health (DPH) recommends a dual water sample be obtained by a State Listed Radon Professional to achieve accurate testing results. Because this testing method is not a federal regulation, not all testers follow the proper protocol. At Tiger, our Certified Environmental Technicians follow the recommended protocols for testing to ensure accurate results.

There is currently no federal standard for radon in water. However, the DPH has a recommended guideline of 5,000 pCi/L in private well water. This is only a guideline with no statutory or regulatory authority. Unable to locate ny guideline, does not appear to be one. Massachusetts offers an “Action Limit”; When concentrations of Rn-222 in water equal or exceed the Action Limit of 10,000 pCi/l, indoor air should be tested (see paper written by K. Martin and C.R. West; March, 1987). 

How Can I Reduce Radon in My Well Water?

Two systems are currently available for treating water with elevated radon. The whole house granular activated carbon (GAC) filter system can be used to treat water with radon levels between 5,000 and 10,000 pCi/L. An Aeration System is a larger investment but effective on all levels of radon in water.

Both of these systems are under constant development, and a number of variations of each system are on the market. Be certain that you purchase a system that is capable of treating the highest level of radon that may be expected in your well. For information on mitigation techniques and licensed contractors check with the CT State Radon office or visit Tiger’s Contractor Network.

Where Can I Obtain Additional Information?

Visit the EPA website: www.epa.gov or contact your state radon office at:

CT (860)509-7367   RI (401)222-5960

NY (518)402-7556    MA (413)586-7525

Request the following EPA publications:

  • A Citizen’s Guide to Radon
  • Home Buyer’s and Seller’s Guide to Radon
  • Consumer’s Guide to Radon Reduction
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