Radon and Iowa Home Sales: Disclosure, Testing, and Negotiation
Iowa has the highest residential radon levels in the United States. According to the Iowa Department of Health and Human Services, more than seven in ten Iowa homes test above the EPA action level of 4.0 pCi/L. That fact shows up in every Iowa home sale — usually as a buyer's inspection contingency, occasionally as a closing-day surprise, and increasingly as a marketing factor sellers think about before they list.
Whether you're a buyer, a seller, or a Realtor working with either, this guide walks through how radon typically plays out in an Iowa home transaction, what the disclosure rules actually require, and how mitigation gets paid for in practice.
Iowa's radon disclosure requirements (the short version)
Iowa real-estate law requires sellers to disclose to buyers what they know about radon in the property. Specifically, the standard Iowa Residential Property Seller Disclosure form asks about:
- Whether the seller has had the property tested for radon
- The results of any prior radon test
- Whether the property has a radon mitigation system installed
- Any known information about radon levels in the home
What the law does not require:
- Sellers are not required to test for radon before selling.
- Sellers are not required to mitigate before selling, even if they know levels are high.
- Buyers are not required to test during inspection.
In other words: Iowa is a disclosure state, not a test-or-mitigate state. What you know, you must tell — but you're not obligated to find out. This matters because what often happens in practice is the buyer orders a radon test as part of the inspection, and the result becomes a negotiation point.
How radon usually shows up in an Iowa transaction
The most common path runs like this:
- Buyer makes an offer with an inspection contingency. Most Iowa contracts include radon testing as part of the standard inspection scope, alongside the home inspection, pest, and well/septic if applicable.
- The radon test runs during the inspection period. A short-term professional test (usually 48 hours, run by the home inspector or a separate radon professional) gives a result during the contingency window.
- Result comes back. Given Iowa averages, there is roughly a seven-in-ten chance the result is above 4.0 pCi/L.
- Buyer responds. If the result is above the action level, the buyer can request mitigation as a condition of closing, ask for a credit, or — less commonly — walk away from the contract.
- Negotiation. Seller and buyer (through their agents) agree on who pays and on what timeline.
Who pays? Three common patterns in Iowa
There's no Iowa law dictating who pays for mitigation in a real-estate transaction — it's purely contract negotiation. Three patterns are most common:
Pattern 1: Seller pays for mitigation before closing
The seller hires a licensed mitigator, the system is installed before the closing date, and a post-mitigation test confirms the level is below 4.0 pCi/L. The buyer takes possession with a working system already in place. This pattern is common when there's plenty of time before closing and the seller wants to keep the deal moving.
Pattern 2: Seller credits the buyer at closing
The seller agrees to a closing-day credit — typically the cost of a standard mitigation install, give or take — and the buyer arranges mitigation after they take possession. Common when the closing date is tight or the buyer prefers to choose their own contractor. Iowa lenders generally allow this.
Pattern 3: Buyer accepts the home as-is
The buyer decides the high reading isn't a deal-breaker and proceeds without asking for mitigation. Less common when the reading is significantly above the action level, more common at marginal levels (4.0–6.0 pCi/L) where the buyer plans to do their own long-term test after move-in.
Realtor-specific notes
For Iowa Realtors, a few things are worth keeping front of mind:
- Almost every transaction will have a radon test. Unlike mold or asbestos, which are condition-specific, radon testing has become near-universal in Iowa transactions because of how high the average reading runs. Plan for it.
- Have a preferred mitigator network. When a high reading comes back during a 7-day contingency window, there's no time to vet contractors. Realtors who can pick up the phone and have a licensed mitigator at the property the next day keep deals on track.
- Disclosure is about what the seller knows. If you're listing a home where the seller has never tested, the disclosure form truthfully says "unknown." That's not a violation — it's just a fact. Encourage clients to test before listing if they want to avoid surprises during the buyer's inspection.
- Pre-listing testing is increasingly common. Some Iowa sellers test before listing and either disclose a clean reading (a marketing positive) or quietly mitigate before showings. Either path avoids contingency-period scrambling.
Timeline: how fast can mitigation actually happen?
Closing dates rarely have flexibility. The good news is that Iowa mitigators are used to working on real-estate timelines. A typical sequence looks like:
- Day 0: high radon test result comes in
- Day 1–2: mitigator visits the home and provides a written estimate
- Day 3–7: seller and buyer agree on terms; mitigator scheduled
- Day 7–10: mitigation system installed (most jobs in a single day)
- Day 10–13: post-mitigation test runs (24–48 hours)
- Day 13–14: post-test result documented and provided to closing
Two weeks from "uh oh" to "documented and done" is realistic for a typical single-foundation Iowa home. Tighter timelines are sometimes possible — call the mitigator early and explain the closing date.
Common buyer questions
The seller's old radon test came back at 3.8 pCi/L. Should I retest?
It's reasonable. Radon levels vary seasonally — winter readings are often higher than summer readings because homes are sealed up. A 3.8 pCi/L reading in July might be 5.5 pCi/L in January. A long-term test (90+ days) gives the most accurate picture. Some buyers run a short-term test during inspection and follow up with a long-term test after move-in.
The seller has a mitigation system. Do I still need to test?
Yes. A mitigation system can fail (the fan can wear out or be unplugged), so the buyer's inspection should still include a test. If the test comes back below 4.0 pCi/L, the system is working. If it comes back above, something's wrong with the existing system and the seller should address it before closing.
Can the seller refuse to mitigate?
Yes — the seller is not legally required to mitigate. But refusing during a buyer's inspection contingency typically gives the buyer the right to walk away from the contract and get their earnest money back. In Iowa's high-radon environment, most sellers find it easier to negotiate a reasonable credit or mitigate themselves than to lose a deal.
Common seller questions
If I mitigate before listing, can I market the home as "radon-mitigated"?
Yes, and many Iowa sellers do. A documented mitigation system with a recent post-mitigation test below 4.0 pCi/L is a marketing positive — it tells buyers that one of the most common Iowa inspection issues has already been resolved. Keep documentation from the mitigator handy for the listing file.
What if I don't know whether my home has high radon?
That's most Iowa sellers. The disclosure form lets you say "unknown." You're not required to test before listing. If you'd rather know in advance, a long-term test kit ($20–$30 from any hardware store) takes about 90 days. A faster short-term test through a mitigator gives a reading in 2–7 days.
The buyer's test came back high but mine was low last year. What now?
Talk to your agent and the buyer's agent. Some negotiation usually follows. Possibilities include: a long-term test to settle the question (often impractical given closing dates), a re-test by a different inspector, or moving forward with mitigation despite the prior low reading. Radon levels do fluctuate, so two different readings on the same home are not unusual.
Get a real-estate-timeline estimate
If you're working through a closing-window radon issue right now, time matters. Pick up the phone — most local Iowa mitigators can get to a home within a day or two and turn the work around inside the typical inspection contingency window.
This article describes typical Iowa real-estate practice and current disclosure requirements. It is not legal advice. Iowa real-estate law can change, and individual transactions can have unique circumstances — consult your real-estate agent or attorney for advice specific to your transaction.