Radon isn’t the most exciting part of buying a home, but in Sioux Falls it’s one of the most important — and one of the most overlooked. Our area has genuinely elevated radon levels, and the good news is the problem is cheap and straightforward to fix once you know about it. Here’s what every buyer and seller in the metro should understand.
What radon is — and why Sioux Falls cares
Radon is a colorless, odorless radioactive gas that seeps up from the soil and can accumulate inside homes, especially in basements and lower levels. It’s the second-leading cause of lung cancer in the U.S. after smoking. You can’t see or smell it — the only way to know a home’s level is to test.
And this is where Sioux Falls stands out: Minnehaha County is an EPA Radon Zone 1 — the highest-risk category, meaning the predicted average indoor level is above the EPA’s action threshold. In practice, county testing data has shown average radon readings around 6.5 pCi/L, well above the 4.0 pCi/L level at which the EPA recommends taking action. Eastern South Dakota broadly falls in Zone 1, so this isn’t a one-neighborhood issue — it’s regional.
What the numbers mean
- Below 2.0 pCi/L: Low; generally no action needed, though no level is risk-free.
- 2.0–3.9 pCi/L: Consider mitigation; the EPA suggests weighing it.
- 4.0 pCi/L and above: The EPA recommends installing a radon mitigation system. Given local averages, plenty of Sioux Falls homes land here.
Testing during a home purchase
The simplest path: include a radon test as part of your inspection period. A short-term test placed in the lowest livable level of the home for a few days gives you a reading before your inspection contingency expires. Because our area’s levels are so commonly elevated, I treat radon testing as a default for buyers here, not an afterthought — it’s a small cost for real peace of mind.
If the result comes back high, it’s not a reason to panic or walk away. It becomes a normal negotiation point: you can ask the seller to install a mitigation system before closing, credit you for it, or split the cost.
Mitigation: cheaper than people expect
A radon mitigation system — essentially a sealed pipe and a continuous fan that vents soil gas safely above the roofline — is a well-understood fix installed by specialized contractors. It’s typically a modest one-time cost relative to the price of a home, and it reliably brings levels down. Many Sioux Falls homes, especially newer ones, are already built “radon-ready” or have a system in place; a system that’s already installed is a selling point, not a red flag.
For sellers: get ahead of it
If you’re selling and you know radon is common here, testing (and mitigating if needed) before you list removes a predictable buyer objection and keeps it from becoming a last-minute negotiation or a deal-killer during the inspection. A documented low reading or an existing mitigation system is a quiet confidence-builder for buyers.
Frequently asked questions
Is radon a problem in Sioux Falls?
Yes. Minnehaha County is classified as EPA Radon Zone 1, the highest-risk category, and local testing data shows average levels around 6.5 pCi/L — above the EPA’s 4.0 pCi/L action level. Eastern South Dakota broadly falls in Zone 1, so radon testing is recommended for essentially every home in the Sioux Falls area.
What radon level requires action?
The EPA recommends taking action at or above 4.0 pCi/L by installing a radon mitigation system. Levels between 2.0 and 3.9 pCi/L are worth considering for mitigation. No level is completely risk-free, but 4.0 is the standard threshold for action.
Should I test for radon when buying a home in Sioux Falls?
Almost always, yes. Because the Sioux Falls area has commonly elevated radon, a short-term radon test during your inspection period is a small, smart investment. If the level is high, you can negotiate for the seller to install a mitigation system, credit you, or share the cost before closing.
Does a radon mitigation system hurt a home’s value?
No — if anything it helps. An installed, working mitigation system means the radon issue has already been addressed, which reassures buyers. In a high-radon area like Sioux Falls, an existing system is generally viewed as a positive, not a defect.
Related Sioux Falls guides
- New Construction vs. Existing Homes — inspection considerations for each
- Buy a Home in Sioux Falls — inspections, contingencies, and the full process
- Sell My Home in Sioux Falls — prep that prevents inspection surprises
Buying or selling and have radon questions?
I’ll make sure radon testing is handled the right way in your transaction — and if a level comes back high, I’ll negotiate the fix so it’s the seller’s problem to solve, not your surprise to absorb. Let’s talk.
This article is general information, not medical or professional advice. Radon levels vary home to home — always test the specific property and consult a certified radon professional. For more, see the South Dakota Department of Agriculture & Natural Resources radon program and the EPA.