Our builder included passive radon mitigation as standard. From what I understand, it is not too much work to convert that into active if later tests show it is needed. One benefit of doing at least passive now, is that it can be a simple roof penetration instead of having the white pvc on the outside of the house as it is typically done on retrofit systems.

@pcxt i didn’t even think about that. I hate the ugly white pipe on our current home

Minnesota requires at least a passive radon mitigation system in all new homes. Fairly easy to install and fairly easy to upgrade to an active system. The plus is that a passive system can help eliminate any dampness in the basement by providing a way for moisture to evaporate from under the basement floor.

No need to test, and you can't get readings in an open house anyway.

A location allowing a straight run of 4" vertical pipe all the way through the roof should be pinpointed and at minimum a 3" PVC 'Tee' put into the gravel base at that location (with a stub that will extend through the concrete). A better solution is to install a 3" perforated pipe loop around the footprint within the gravel base that is connected to that Tee. The vapor barrier should have it's seams overlapping min 12" or have sealant. Doing at least these will make it so much easier later.

Just a capped stub from only a "Tee" should be minimal cost, but if you can afford a larger change order now, have the builder install the passive system complete. Do the perforated underslab loop. Run the pipe through the roof. Install power to where a future fan would go in the attic. Seal any slab penetrations. Provide a sealed sump pit cover.

After you have lived there a year, then test for radon levels. If you are high at that point, a fan may be all you need to make it an active system.

haylo33 - We added the passive system. Had one in the last two homes. Last home, before closing, we had to convert it to an active system.