Radon test results may be reported in three different measures – picocuries (pCi/l), Working Levels (WL) and bequerels (bq). If your test result is in pCi/L, EPA recommends you fix your home if the radon level is 4 pCi/L or higher. If the test result is in WL, EPA recommends you fix your home if the working level is 0.016 WL or higher. Some states require WL results to be converted to pCi/L to minimize confusion. While not commonly used in the United States, any radon level at or above 0.148 bq should be reduced.
Find your state radon coordinator at www.epa.gov/radon/find-information-about-local-radon-zones-and-state-contact-information.