Radon Testing in Sioux Falls
You cannot smell it, see it or feel it, so the only thing that exists is the number. All of South Dakota is EPA Zone 1. A 48-hour test tells you where you stand, and if you need a system we guarantee below 2.0 pCi/L with the retest included.
Radon Is a Number, Not a Feeling
Every other problem in a house announces itself. Water stains. A smell. A draught. Radon does none of that — it is a colourless, odourless gas that seeps out of the soil through the slab, and the only way anyone has ever known they had it is by measuring.
That is the entire reason this trade exists and the entire reason people put it off. There is no symptom to prompt the call. In South Dakota, where the whole state sits in EPA Zone 1 and average indoor levels run well above the national figure, the base rate is high enough that testing is simply the sensible default.
- ✓Colourless, odourless — a test is the only signal that exists
- ✓All of South Dakota is EPA Zone 1, the highest-potential category
- ✓A 48-hour closed-house test gives you the number
- ✓The test result is yours regardless of who does any mitigation
Measure, Mitigate, Measure Again
The last step is the one that separates a system from a fan making noise.
We do not do foundation work, waterproofing or crawl-space insulation. We measure radon and we lower it — anything else in your basement is somebody else's trade.
Reading a Radon Result Without the Panic
The units are picocuries per litre. Here is the honest interpretation of each band, including the part where the thresholds are somewhat arbitrary.
Under 2.0 · leave it alone
Around the level of outdoor air in much of the country. There is no such thing as zero radon and chasing it below this is not a good use of money. This is also the number we guarantee to get you under.
2.0 to 3.9 · your call, and a real one
Below the EPA action level, above the WHO reference level of 2.7. The EPA says consider fixing. At the top of this band a system is a defensible decision, particularly if anyone sleeps in the basement.
4.0 to 10 · fix it
The EPA action level is 4.0 and this is the band most Sioux Falls houses that test high land in. A standard single-point system takes almost all of it out.
Over 10 · fix it now, and retest after
Not an emergency in the sense of leaving the house tonight — the risk is cumulative over years, not acute. But it is the band where we will fit you in this week rather than next month.
Why the threshold is not a safety line
4.0 was set as an achievable target, not a point below which radon is harmless. Risk falls continuously as the number falls. Anyone who tells you 3.9 is safe and 4.1 is dangerous is reading the table wrong.
Test, Install, Retest
About a week end to end, and one working day of that is in your house.
Test
48 hours with a continuous monitor under closed-house conditions. You get the hourly chart, not just an average, so a single weather anomaly is visible rather than hidden.
Diagnose
A communication test tells us how far suction travels under your slab. That decides one suction point or two, and it is why we do not quote from a photograph.
Install
One working day for most houses. Core the slab, seal, pipe to the fan, discharge above the roofline, fit the manometer and label the system.
Retest
48 hours again, included. If it is not under 2.0 we return and modify the system at our cost until it is.
What It Actually Looks Like On A House
The question we get asked more than price: how visible is it? Usually a single pipe run and a fan, placed where you would not lead a visitor. Here are two we finished this year.
A System Nobody Retested Is a Fan Making Noise
Here is the uncomfortable thing about this trade: once the pipe is on the wall and the fan is humming, the job looks finished. The homeowner cannot tell the difference between a system taking a house from 12 to 1.1 and one taking it from 12 to 6.
Only a retest can. We include one on every install and we put a number in the contract — under 2.0 pCi/L, or we come back and modify the system at our cost. That has meant returning to extend suction points and, twice, adding a second point we had not charged for. It is the right way round: we carry the risk of our own diagnosis, not you.
- ✓Retest included on every install, never billed as an extra
- ✓Written guarantee of under 2.0 pCi/L
- ✓If it misses, we modify the system at our cost
- ✓You get both charts — before and after — as a PDF
What People Say
We tested at 11.4 because our realtor insisted. I had lived in that house for nine years with two kids. The system took it to 1.1 and cost less than the fridge we bought that same month.
The retest came back at 2.6 — better, but not where they wanted it. They came back, extended the suction point and re-ran it at no charge. Final number 0.9. That is the part nobody else offered in writing.
They talked me out of a second suction point I had been quoted elsewhere. Said one would do it on a slab that size and if it did not they would add the second free. It did.
Never Tested? That Is the Whole Point.
There is no symptom to wait for. A 48-hour test gives you the number, and most houses that test come back fine.
Radon, Without the Scare Tactics
How dangerous is radon, really?
It is the second leading cause of lung cancer after smoking, and the risk is cumulative over years of exposure rather than acute. That means a high reading is a thing to fix within weeks, not a reason to leave the house tonight. We would rather say that plainly than sell on fear — the honest case for testing is that it is cheap and the base rate here is high.
What does mitigation cost in Sioux Falls?
$1,200-$2,500 for a standard single-point sub-slab system, including the post-mitigation retest. Crawl space membrane systems run $1,800-$3,500 depending on area. A second suction point adds $400-$700. Running the fan costs roughly $5-$10 a month in electricity.
Why is South Dakota so bad for radon?
Glacial soils and the underlying geology. The entire state is EPA Zone 1 — the highest-potential category — and average indoor readings here run well above the national figure. It is not a reflection on your house; it is what is under it.
Can't I just seal the cracks in my basement floor?
No, and this is the most common misunderstanding. Sealing alone typically produces a small, unreliable reduction because soil gas will find any remaining path. Mitigation works by creating suction under the slab so the gas goes up a pipe instead. Sealing supports that; it does not replace it.
Do the fans need maintenance?
They run continuously and last around ten years. The maintenance is checking the manometer — that little U-shaped gauge on the pipe. If the liquid in both legs is level, the fan has stopped and the system is doing nothing. We fit it at eye level and show you what to look for.
Will a system make my house cold or noisy?
A correctly installed fan is a low hum you stop noticing, and it is outside the living space by code. It does move a small amount of conditioned air, but on a properly sealed slab the effect on your heating bill is minor — smaller than the fan's own electricity cost.
We're selling. How fast can this happen?
Usually within a week: test, install, retest. We send reports straight to the title company and we are used to closing timelines. If the buyer's inspection turned up a number, call us before you renegotiate — mitigation is almost always cheaper than the credit that gets asked for.
Do I need a test if my neighbour's was fine?
Yes. Readings vary enormously between adjacent houses because they depend on the soil directly beneath, the foundation type and how the house is sealed. We have tested houses on the same street where one read 1.2 and the other 14.