Radon mitigation pipe stainiing

Radon mitigation system installed in home today. I noted staining on the PVC pipe in the basement but only in the basement piping and not on the whole pipe and not anywhere else. Any ideas? Is this mold? and why would it be on the pipe only? Could it of been on the pipe during installation? System put in about 6 years ago.

Condensation making moisture from the temperature differential (a radon pipe in the basement area is usually cooler because it is pulling out ground temperature air). As for mold, most likely - but not sure. I see it a lot on radon pipes and well pipes

Thanks Ian, Most of the staining was where the pipe exited the slab and ran about 12-15 feet before it dissipated. Possibly the the air warmed upped as it was drawn through the pipe? I don’t think this is a situation where I need to call for an assessor.

Yep, that is typical. Usually by the time the pipe hits the first floor the air is warmed up. As for an assessor, anything over 10 sq ft according to the law, so use your judgement.

Consider this… a 10 ft section of pipe with a circumference of 12 inches would be the limit… BUT… all of the white space surrounding the (suspected) mold spores is not (suspected) mold, so subtract the white space from the total and you are good to go! :razz: