radon retest 2

https://mysubslabdepressurizationpost.meridiannest.com/posts/why-sub-slab-depressurization-is-the-gold-standard-in-radon-mitigation

A radon retest is simply taking a second measurement of radon levels in your home. This usually happens after you've done mitigation work, like sealing cracks or installing a vent system. The goal is to confirm that your fix actually worked and that the gas levels have dropped below the EPA's recommended action threshold of 4 picocuries per liter. It's best to wait at least 24 hours after mitigation and to place the test kit in the same location as before for a fair comparison.