If a post-mitigation test result is below 4.0 pCi/L, when is it recommended to test the home again?

The recommended time frame for retesting a home after a post-mitigation test result shows radon levels below 4.0 pCi/L is typically in 2 years. This guideline is set to ensure that the mitigation system continues to function effectively and that any potential changes in radon levels can be monitored appropriately.

Regular retesting helps to account for fluctuations that may occur due to various factors, including changes in the environment or the home itself. Since radon levels can change over time due to various influences, waiting for 2 years provides a reasonable balance between ensuring safety and the practicalities of testing.

Mitigation systems can also vary in effectiveness over time, and periodic checks ensure that the system is still effectively reducing radon levels. Testing at 2-year intervals has become a standard recommendation that supports ongoing safety and health in environments previously known to have elevated radon concentrations.