If you are buying or selling a home in Iowa City, radon testing is not an optional extra. Iowa has the highest average indoor radon levels in the nation, and roughly 7 in 10 Iowa homes test at or above the EPA action level of 4.0 picocuries per liter. Johnson County sits in EPA Radon Zone 1, the designation for areas with the highest radon potential.
That means the odds are better than not that the house in your purchase agreement has a radon problem. The good news is that testing is quick and affordable, mitigation is a well-understood fix, and none of it has to derail your closing if it is handled early in the inspection period.
We provide real estate radon testing throughout Iowa City, Coralville, North Liberty, Tiffin, Solon, University Heights, and the rest of Johnson County, following real estate testing protocols that both agents in a transaction can rely on. We are certified through the Iowa Department of Health and Human Services radon program, as Iowa law requires of anyone offering radon services professionally.
The Inspection-Period Clock: Why You Need to Schedule Fast
Most purchase agreements in the Iowa City market give buyers a limited inspection window, often seven to ten days, to complete all inspections and deliver any objections. A valid radon test takes a minimum of 48 hours of continuous measurement, and the home needs to be under closed-house conditions, meaning windows shut and doors used only for normal entry and exit, for 12 hours before the test starts and for the full test period.
Work backward from your objection deadline and the math gets tight quickly. You need a day to schedule and place the monitor, two full days of testing, and time to review the written report and decide how to respond. If the radon test is an afterthought scheduled after the general home inspection, you can run out of runway.
Our advice to buyers and agents is simple: order the radon test the same day the purchase agreement is accepted. We can typically place a monitor within one business day, which keeps the entire test comfortably inside a standard inspection period with room to negotiate if the result comes back high.
How a Real Estate Radon Test Differs From a Standard Test
A homeowner testing their own house can use a charcoal kit from the hardware store and wait a few weeks for lab results. A real estate transaction cannot. The test has to be fast, defensible, and trusted by two parties with opposing financial interests, so the protocol is stricter.
We use continuous radon monitors, or CRMs, placed in the lowest livable level of the home. A CRM records radon concentrations hour by hour for the full 48-hour test, which does two things a passive kit cannot: it produces results immediately when the monitor is picked up, and the hourly data reveals tampering. If someone opens windows to vent the basement mid-test, the pattern shows it.
Because the seller still occupies most homes under contract, tamper resistance matters. We document monitor placement, log closed-house conditions, and deliver a written report with the hourly readings, the overall average, and a clear pass-or-fail against the 4.0 pCi/L action level. Listing agents and buyer's agents both get a report they can put in the file without argument.
Iowa's Seller Disclosure Law and Radon
Under Iowa Code chapter 136B, home sellers must disclose known radon test results and any radon mitigation efforts as part of a residential real estate transaction. If the house was tested five years ago and came back at 6.2 pCi/L, that belongs on the disclosure. If a mitigation system was installed, that belongs there too.
For buyers, the disclosure is a starting point, not a substitute for testing. Radon levels change over time, a past test may have been done poorly, and many homes have simply never been tested at all, which means there is nothing to disclose. A current 48-hour CRM test during your inspection period is the only way to know what the house measures today.
For sellers, the disclosure duty is a reason to test on your own terms rather than waiting for the buyer's result to surprise you. Once you have a test result, you know it, and knowing it means disclosing it, so it pays to be the one who controls the timing.
When the Test Comes Back High: Negotiating Mitigation
In a market where roughly 7 in 10 homes test at or above 4.0 pCi/L, a high result should be treated as a normal, solvable inspection finding rather than a reason to walk away. The standard fix is an active sub-slab depressurization system: a sealed suction point through the slab, a vent pipe, and a continuously running fan that pulls radon from beneath the foundation and exhausts it above the roofline.
In the Iowa City area, a typical mitigation system installation runs about $900 to $1,400 depending on the foundation type and the routing of the vent pipe. That is a small number relative to the transaction, which is exactly why radon findings rarely kill deals here.
Who pays is a negotiation. Buyers commonly request that the seller install the system before closing or credit the cost at closing. Sellers sometimes prefer the credit so the buyer selects the installer. Either way, the fix should be performed by an Iowa-certified mitigation professional, and a post-mitigation retest should confirm the level is below 4.0 pCi/L before everyone signs off.
Sellers: Test Before You List
The strongest position a seller can hold in Johnson County is a recent test result and, if it was high, a mitigation system that is already installed and verified. Pre-listing testing turns radon from a mid-contract crisis into a bullet point in your marketing.
Consider the alternative. The buyer's test comes back at 9 pCi/L eight days before your objection deadline, and now you are negotiating a repair under time pressure with a buyer who feels entitled to concessions. Testing before you list costs roughly $150 to $250 and eliminates that scenario entirely.
If your pre-listing test is high, installing mitigation before the sign goes in the yard usually costs the same $900 to $1,400 it would cost mid-transaction, but you choose the schedule and the contractor. A disclosed, functioning mitigation system with a passing retest is an asset in this market, not a red flag.
New Construction Is Not Automatically Safe
Buyers of newly built homes in Coralville, North Liberty, and Tiffin often assume radon is an old-house problem. It is not. Radon comes from uranium decaying in the glacial soils under the foundation, and a brand-new slab poured over Johnson County ground faces the same soil gas as a 1920s basement in Iowa City.
Many new homes here include passive radon rough-ins: a vent pipe stubbed from below the slab up through the roof, with no fan. Passive systems help, but they frequently are not enough on their own, and homes with passive rough-ins still test above 4.0 pCi/L regularly.
The upside is that activating a passive system is the cheapest mitigation there is, since the pipe is already in the walls and only a fan and electrical connection are needed. Test the new house during your inspection period like any other. If it is high, activating the rough-in is a simple, inexpensive ask of the builder.
Fast Turnaround for Agents Across Johnson County
Real estate agents are most of our repeat callers, and we have built our process around what a transaction needs: quick scheduling, coordinated access through the listing agent or lockbox, monitor placement that respects the seller's home, and a plain-English written report delivered the same day the monitor comes out.
We serve Iowa City, Coralville, North Liberty, Tiffin, Solon, University Heights, and the surrounding rural Johnson County addresses. Whether the property is a condo near the University of Iowa campus, a duplex held as a rental, or an acreage outside Solon, the protocol and the turnaround are the same.
If you have an accepted offer and an inspection deadline, call us or send the lead form today. We will get a continuous monitor placed quickly, run the full 48-hour test under closed-house conditions, and put a report in both agents' hands with time left on the clock to act on it.