radon manometer reading 5

https://atomic-wiki.win/index.php/When_to_Call_a_Radon_Contractor_St_Louis_Homeowners_Can_Trust

I checked the radon manometer reading in the basement this morning, and it was sitting at 4.2 pCi/L, just above the EPA action level. The digital display showed a steady number without much fluctuation, which usually means the sensor is working fine. I might need to install a mitigation system soon to bring it down.