Testing for Radon

How Radon Enters Our Homes by the Center for Disease Control and Prevention

Where Can I Get a Test Kit?

The National Radon Program Services at Kansas State University offers discounted test kits available to purchase online. Click here to order a test kit.

About Radon Test Kits

The North Carolina Radon Program recommends having your home tested by a certified professional. If you choose, however, to test your home utilizing a DIY test kit, following are the companies that manufacture and sell radon test kits. They each conduct their own analysis of their test kits.

Testing Process

Step 1. Test your home using a short-term test. If your result is 4 pCi/L or higher, take a follow-up test (Step 2) to be sure.

Step 2. Follow up with either a long-term test or a second short-term test:

For a better understanding of your year-round average radon level, take a long-term test. If you need results quickly, take a second short-term test.

Note: The higher your initial short-term test result, the more certain you can be that you should take another short-term test rather than a long-term follow up test. If your first short-term test result is more than twice EPA’s 4 pCi/L action level, you should take a second short-term test immediately.

Step 3. If you followed up with a long-term test: Fix your home if your long-term test result is 4.0 pCi/L or more.

If you followed up with a second short-term test: The higher your short-term results, the more certain you can be that you should fix your home. Fix your home if the average of your first and second test is 4 pCi/L or higher. Many homes can be mitigated to 2 pCi/L or lower, consider fixing your home if the levels are 2-4 pCi/L.

Who Should I Hire to Test for Radon?

Testing for radon is to understand what average level of radon are people being exposed. The test should be conducted for no less than 48 hours and tested on the lowest occupied level of the building.

The NC Radon Program highly recommends hiring a trained radon measurement professional. The NC Radon Program cannot endorse any particular certification company or individual, so we recommend researching the individuals’ qualifications and asking for references. Below are links to the three organizations that provide radon testing certifications.

When Hiring a Certified Measurement Provider

Does the measurement provider utilize a continuous radon monitor or a test kit. Both are viable tools for measuring radon. A CRM, however, can provide hourly information (such as temperature, humidity levels, etc.) that a certified radon professional can utilize to help the homeowner understand the radon level.

If a CRM is being utilized, is the CRM being properly maintained and calibrated. A label on the CRM would indicate any expirations.

Will the certified professional provide you with an hour by hour measurement with an analysis of the test result or will they provide you with an average test number without analysis? It is least likely that you will receive an analysis with a single number average. 

Test results without analysis have presented, in the past, disagreements between the buyer and seller as to whether environment influenced the test result. A written analysis may be of help to both parties in the real estate transaction.

A copy of the protocols for testing for radon can be found at https://standards.aarst.org

Testing for Radon in Private Well Water

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

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. 

A copy of the protocols for testing for radon in private well water can be found at https://standards.aarst.org