Can a manufactured home have radon if it sits on a crawlspace?

Yes. The belief that a home on piers cannot have a radon problem is one of the more persistent and more dangerous misunderstandings in this region. An enclosed, skirted crawlspace over bare soil is a radon reservoir, and the same failures in the bottom board that let ground moisture into the floor cavity let soil gas into the living space by exactly the same path. The openings cut for ducts, plumbing and the crossover duct are direct pathways, and the stack effect of an Iowa or Minnesota winter is the pressure difference that pulls soil gas up through them. This matters because the regional risk is real: the EPA designates the entire state of Iowa as Zone 1, its highest radon potential classification, and Iowa HHS states that the Iowa Radon Survey found Iowa has the largest percentage of homes above the EPA action level of 4 pCi/L in the nation, at 71.6 percent. The Minnesota Department of Health reports that more than two in five Minnesota homes have radon levels that pose a significant health risk. None of that carves out manufactured homes. Two things differ from testing a house with a basement. First, what gets tested: the lowest lived-in level of the home, not the crawlspace, which is not occupied space. Second, what mitigation looks like if the result is high. There is no slab to depressurize, so the typical approach is sub-membrane depressurization — a continuous vapor barrier sealed over the crawlspace soil with suction drawn beneath it — or crawlspace sealing and encapsulation with a fan-driven vent stack, and repairing the bottom board and sealing penetrations is often part of the fix rather than an extra. A manufactured home's smaller air volume can also make results more sensitive to conditions during the test, which makes closed-building protocol discipline matter more, not less. If the home sits in a park, ask the park owner about mitigation before you need it, since the system penetrates the skirting and the roofline. Add a radon test when you use the free instant quote tool below.