Active radon mitigation installed but levels are still ~10 pCi/L after a week. Contractor says builder's passive system may be defective. Looking for advice.
I recently had my builder-installed passive radon system converted to an active system by Midwest Radon Services and I'm looking for advice from anyone who's dealt with a similar situation.
Background
- House: Townhome with finished basement in Aurora, IL, 2017 built
- Existing builder-installed passive radon system
- EcoQube monitor has been installed in the basement for several months
- Monthly averages before mitigation:
- Apr–May: 3.8 pCi/L
- May–Jun: 9.1 pCi/L
- Jun–Jul: 8.4 pCi/L
Because the levels stayed elevated for a couple of months, I decided to convert the passive system to an active one.
What Midwest Radon Services did
- Installed an RN2ec fan
- Sealed/replaced the sump pit cover
- Performed a Pressure Field Extension (PFE) diagnostic test and it read a negative number which they said was a wonderful thing
- Manometer reads about 0.7" w.c., and they said the diagnostic numbers looked good.
The problem
It's now been about 7 days since the installation, and my EcoQube is still averaging around 10 pCi/L over the last few days.
I contacted Midwest Radon Services, and they replied:
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However, they also said there would be:
- a charge for another site visit/diagnostic, and
- additional charges depending on what actual work is needed.
My questions
- Is it normal for an active mitigation system to still be around 10 pCi/L after a week, or should I expect a much larger reduction?
- Has anyone had a builder-installed passive system that had to be reworked after converting it to active?
- Does Midwest Radon's explanation sound reasonable?
- Would you expect to pay another diagnostic fee in this situation, or would you expect the contractor to first verify why the newly installed system isn't reducing radon?
- Should I get a second opinion from another mitigation company before authorizing additional work?
I'm not trying to blame the contractor but genuinely want to understand whether this is a normal scenario or whether I should push for more explanation before paying for additional work. Or should I simply contact other contractors for this?
Any advice from radon professionals or homeowners who have gone through this would be appreciated. Thank you!