Radon in Sibley County

Radon is the leading cause of lung cancer in non-smokers, and south-central Minnesota is a high-radon region. The Minnesota Department of Health reports that the majority of homes tested in this part of the state come back above the EPA action level of 4.0 pCi/L. For Winthrop buyers, radon measurement is not optional caution — it is baseline diligence.

Why our geology drives it

Radon is a soil gas. It enters through foundation cracks, sumps, and slab penetrations and accumulates in the lower levels of a closed-up house — exactly the conditions of a Minnesota winter. The local soils and bedrock release enough radon that even newer, tight homes routinely test high.

How it is measured

An EPA-protocol continuous monitor runs a minimum of 48 hours under closed-house conditions. Continuous monitoring resists tampering and shows the hour-by-hour pattern, which is more trustworthy than a single passive canister for a real estate transaction.

What to do about a high result

Mitigation — typically a sub-slab depressurization system installed by a certified contractor — is highly effective and well understood. A high radon result is not a deal-breaker; it is a fixable, negotiable item. The deal-breaker is not testing at all.

Why even new homes test high here

It is a common misconception that radon is an old-house problem. It is a soil-gas problem. A brand-new, tightly built Winthrop-area home sitting on the same soil can — and often does — test above the action level, because the tight envelope holds the gas in. New construction is not a reason to skip the test.

Mitigation is routine and effective

Sub-slab depressurization, installed by a certified contractor, reliably brings levels down and is a well-understood, code-recognized system. A high result is a negotiation item with a known fix — never a reason to abandon a house you otherwise want.

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