If you are closing on a new build in Prairie Trail or The District at Uptown this year, do you still need to test for radon?
Most buyers assume the answer is no. As of July 1, 2026, Iowa's building code requires passive radon mitigation in every new single- and two-family home built in the state, so the thinking goes that the problem has already been engineered out before the drywall goes up. That assumption is the single most common mistake I see new-construction buyers make in Ankeny, and it is worth correcting before you are standing in a closing that hinges on it.
What the New Code Actually Guarantees
A passive radon system is a rough-in: PVC piping run from a sub-slab collection point up through the house to a roof vent, sealed penetrations, and a spot reserved for a fan if one is ever needed. It lowers the odds that a home tests high. It does not lower them to zero, and it does not replace testing.
Polk County required radon-resistant construction in new builds before this became a statewide rule, and cities including Altoona and Bondurant have had their own versions on the books for years. Ankeny's building department has been operating in that same spirit for a while. What changed as of July 1, 2026 is that the requirement stopped being a patchwork of local ordinances and became the baseline for every new single- and two-family home in the state. That is a meaningful shift for construction quality. It is not a substitute for a 48-hour test once the house is built and closed up.
If you are comparing a new build against a resale in Ankeny this year, the honest way to think about it is this: the new home starts with a passive system already in the walls, which is genuinely useful. The resale home may or may not have one. Neither fact tells you what the actual reading will be. Only a test does.
The Geology Doesn't Know What Year the House Was Built
Ankeny sits in Polk County, which the EPA designates as Zone 1, its highest-risk radon category. That designation exists because of what is under the ground, not what is on top of it. Glaciers that retreated across Iowa thousands of years ago left behind soil deposits rich in uranium and radium. As those minerals decay, they produce radon gas, and the gas moves upward through porous soil until it finds a crack, a sump pit, or a utility penetration to enter a building through.
That process does not check a permit date. A 2026-built home in a new Prairie Trail subdivision sits on the same glacial soil as a 1998 split-level three streets over. The World Health Organization has been direct about what elevated exposure means over time, noting that most radon-related lung cancers come from long-term exposure at low and moderate levels inside people's homes, not from some dramatic one-time event. That is precisely why a passive system in a new build matters less than people think it does. The soil's output does not change. What changes is whether the house is doing anything about it, and a passive rough-in with no fan running is a different thing than a tested, verified system.
What Iowa Law Actually Requires You to Disclose
This is where I see the most confusion, on both sides of a transaction.
Iowa Code Chapter 558A requires sellers of most residential properties to complete a written disclosure statement before a buyer's offer is accepted, and that statement includes a specific radon category. If a seller has test results on file, those results have to be shared. If there is a mitigation system installed, that has to be disclosed too.
What the law does not require is testing before you list. A seller can legally sell a home in Ankeny having never tested it, so long as they are truthful about what they do and do not know. That single distinction, known versus tested, is the entire hinge of how radon plays out in a real transaction. Sellers who test ahead of time and can hand a buyer a clean post-mitigation report are negotiating from a position of documentation. Sellers who skip testing are not breaking the law, but they are also not offering the buyer anything to lean on, which tends to make buyers more cautious, not less.
Buyers carry their own piece of this. Iowa's disclosure law does not obligate a seller to test, so the responsibility to find out what is actually happening in the house falls on the buyer's inspection contingency. A radon test typically runs a straightforward 48 hours using a continuous monitor, and it is worth scheduling it in the first day or two of your inspection period rather than near the end, since your negotiating window is tied to that contingency clock, not to when you happen to get around to it.
What Testing and Mitigation Actually Cost
| Item | Typical Cost | Timeframe |
|---|---|---|
| Radon test (short-term) | $100 to $250 | 48 hours |
| Mitigation install (sub-slab depressurization) | $800 to $2,500, median near $1,400 as of the second quarter of 2026 | Usually one day |
| Crawl space sub-membrane system | $1,500 to $3,500 | One to two days |
| Post-mitigation verification test | Often included with install | 48 hours |
These figures hold across most Ankeny homes with standard basements. Homes with block-wall foundations or unusual crawl space layouts can run higher, which is exactly the kind of detail a licensed contractor confirms during the actual site visit rather than off a general estimate.
A 43 pCi/L Reading Didn't Kill the Deal
There is a documented case from an Ankeny transaction where a buyer's inspection came back at 43 pCi/L, more than ten times the EPA's 4.0 pCi/L action level. That is an alarming number to see in an inspection report. The buyer's agent asked the seller to mitigate as a condition of moving forward. The seller agreed, a system was installed, and the deal closed on schedule.
The lesson isn't that a high number is nothing to worry about. It's that a high number is a line item to negotiate, not a reason to assume the deal is over. Here is roughly how that plays out in practice once a test comes back elevated during an Ankeny inspection period:
- The test result lands, typically a day or two after the monitor is placed and picked up.
- Your agent flags whether your purchase agreement included a radon contingency or whether your general inspection contingency covers it.
- You have a defined window, tied to your contract, to request the seller install or pay for mitigation, renegotiate price, or in some cases walk away without forfeiting earnest money.
- If mitigation is agreed to, a licensed installer typically completes the system in a single day.
- A post-installation test confirms the reading has dropped, which becomes part of your closing documentation.
None of this requires the deal to fall apart. It requires knowing your contingency deadlines and treating the reading as information rather than a verdict.
What This Means If You're Buying or Selling in Ankeny Right Now
If you're under contract on new construction anywhere in Ankeny's growing subdivisions, ask your builder whether the passive system has been tested since occupancy, not just installed during framing. A passive rough-in that has never been verified with an actual reading tells you less than you'd think.
If you're buying resale, don't treat an existing mitigation system as a red flag. It usually means a previous owner already found and fixed the issue, which is a stronger position than a home that has simply never been tested.
If you're financing with an FHA loan, know that FHA does not legally mandate radon testing, but some underwriters in high-radon states request results during the process, and an appraiser can flag elevated readings as a condition to resolve before closing. That's the kind of detail that catches buyers off guard mid-transaction, and it's exactly the sort of financing wrinkle I spend time walking clients through given my background in mortgage lending before I became a broker associate.
Whether you're comparing a resale in an established Ankeny neighborhood against new construction through a builder like Claman Custom Homes, the radon conversation belongs early in your process, not as a surprise line in an inspection report.
A Few Common Questions
Does a passive radon system mean a new-construction home won't need mitigation later? No. A passive system lowers the odds of an elevated reading but doesn't guarantee one. Some homes with passive systems still test above 4.0 pCi/L and need a fan added to make the system active.
If a home already has a mitigation system, do I still need to test it? Yes. A system that hasn't been checked in a while can lose effectiveness, and a post-mitigation test confirms it's actually doing its job rather than just sitting there.
Does a high radon reading lower a home's value? Not on its own. The risk to value comes from an unresolved reading, not a documented one. A home with a verified, working mitigation system and a clean test report is not a lesser home.
If you're weighing a new build against a resale in Ankeny, or you just want a straight answer about what a radon reading means for your specific contract, I'm glad to walk through it with you. Scot Bergman has spent years combining mortgage lending experience with hands-on brokerage work in this market, and a radon number in an inspection report is one more place where that combination helps. Let's Connect.
