Does a low radon air reading necessarily = low radon in well water?

Steve Bull Published: Jan. 4, 2020, 1:45 p.m.Last updated: Jan. 14, 2020, 11:21 a.m.

Our home was recently tested for radon and is at 33 Bq/m3, which I understand is relatively low and does not require any remediation. Does that necessarily mean that, by extension, our well water is low in radon as well? We haven't yet tested it, and don't know if we need to. I do know that a high air reading can be the result of high level of radon in well water. Thanks for your input.

Responses (2)

Steve Bull Jan. 14, 2020, 4:58 p.m. Reply

Mike: Thanks for the qualified answer, and your words of caution (i.e. "get it tested, to be absolutely sure") are well-recieved. 

I do take some comfort in learning (through another information source) that the risk of acquiring a radon-related diease through ingested radon is significantly less than through an air-borne source, despite the fact that our water may (as you say)  be the sole source for whatever small amount that remains in our household air. Further, our drinking water is run through an RO system, with activated carbon filters, which can (I understand) trap some or a lot of radon in the water. So at least we're not drinking radon, or as much of it, if our well is the source for our air-borne radon.

Our house is probably moderately air-tight; its a century home that has been updated, runs a woodstove regularly, but with no HRV. The bathroom fan does run during showers. But... without an air leakage test, its not easy to estimate the rate of air exchange, and draw any definitive conclusions about how much radon is possibly being vented, and how much is being "generated" within the structure. Or from where it may be coming.

We'll look into this further and hopefully eliminate the possibility that well water may be concern.