The Short Answer
We notice that many homeowners view a single test as a lifetime guarantee. That first reading is just a snapshot, because indoor gas concentrations shift as your foundation settles or the seasons change.
The reality is that soil dynamics constantly alter how gas enters your living space.
Here is a simple radon testing schedule specifically built for Iowa homes. When your calendar shows it is time, you can book a radon test with our credentialed technicians.
Let us review the exact guidelines on how often should you test for radon, what the 2026 data actually tells us, and exactly when you should take action.
| Your situation | When to test |
|---|---|
| Never tested | Now |
| Have a mitigation system | After install, then at least every two years |
| Tested low, no system | Every two years and after major changes |
| Finished basement or added living space | After the project |
| New furnace, windows, insulation or air sealing | After the work is done |
| Manometer changed or fan sounds different | Now, after the system is checked |
| Buying or selling | During the transaction |
Rule of thumb
If something about the house has changed, or two years have passed, it’s time to test again.
If You’ve Never Tested
You need to test your property immediately if you have never done so. Our team constantly reminds local residents that every single one of Iowa’s 99 counties falls into EPA Radon Zone 1. This federal designation means the area has the highest potential for dangerous indoor air quality.
In fact, 2026 state data shows the average indoor reading in Iowa is 8.5 pCi/L, which is more than double the EPA action level of 4.0 pCi/L. Nearly 71.6% of homes in the state test above that recommended threshold.
It simply does not matter if your house is brand new, if your neighbor tested low, or if you lack a basement entirely. A baseline assessment is the only scientific way to verify your true exposure risk.
If You Have a Mitigation System
An active mitigation system requires consistent monitoring and a formal inspection schedule. We recommend treating this equipment just like your household furnace, because mechanical parts like fan motors and bearings inevitably wear out over time.
A functioning setup relies on two specific types of ongoing checks.
Retest every two years
The EPA explicitly tells homeowners to schedule a radon retest every two years to ensure the system still pulls sufficient vacuum. Fans degrade, PVC exhaust pipes develop cracks, and new fissures frequently open up in your concrete slab as the ground freezes and thaws.
Our technicians often find that a system installed five years ago no longer moves enough air to keep levels below 4.0 pCi/L. A formal test confirms the equipment is still doing its job correctly.
Check the manometer monthly
You should visually inspect your U-tube manometer at least once a month. This small gauge sits on the PVC pipe and measures the suction created by the exterior fan.
If the liquid in the gauge is uneven, the system is actively pulling soil gas away from your foundation. A level reading at the zero mark indicates a failure, meaning you have lost suction entirely.
Our comprehensive guide on manometer readings explains exactly what to look for and how to troubleshoot common issues.
After Renovations and Home Changes
You must run a fresh assessment after completing any major remodeling or structural updates like pouring a foundation addition. Changes to the building envelope often alter internal airflow, which can unintentionally pull more soil gas indoors.
We always see massive fluctuations in gas levels when a property undergoes significant modernization like a full basement remodel. You should always retest radon after renovation projects to verify your air remains safe.
Finishing a basement
Finishing a lower level is a massive trigger for elevated exposure. A remodeled basement means your family spends much more time on the lowest floor, right where gas concentrations reach their absolute peak.
The construction process itself often opens new pathways for soil gas or unintentionally covers up existing foundation vents. If you already have an active fan, you must keep the PVC pipe, the manometer gauge, and the sump lid fully accessible when building out those new walls.
HVAC changes
A new furnace, central air conditioner, bathroom exhaust fan, or whole-house air exchanger alters the internal pressure of your building. These mechanical upgrades can inadvertently create a stack effect that pulls more contaminated air up through the concrete.
Our local data shows that installing a high-efficiency HVAC setup frequently shifts previously safe readings into the danger zone.
Windows, insulation and air sealing
Tightening up a house with modern spray foam or triple-pane windows saves tremendous energy, but it drastically reduces natural air exchange. Any gas that enters a well-sealed home gets trapped and builds up to much higher concentrations over time.
You should always schedule a fresh test after a professional energy audit project is completed.
Foundation or slab work
Any concrete modification directly impacts how soil gas enters your living space. Pouring a new slab, installing interior French drains, replacing a sump pump, or fixing foundation cracks alters the underground pressure dynamics.
These structural repairs often disrupt the exact pathways the gas originally used to escape, forcing it up into your family room instead.
Before Buying or Selling
If you are buying a home, you should mandate a formal test during the standard inspection period. Sellers should also test their property before listing to prevent last-minute closing delays and buyer hesitation.
We closely monitor local real estate regulations, such as Iowa Code 543B.9, which require sellers to disclose specific information during a transaction. As a seller, you are legally expected to provide:
- Any known prior radon test results.
- Details of existing mitigation equipment.
- A copy of the official state fact sheet.
While testing is not legally mandated for a listing, knowing your numbers ahead of time gives you negotiation leverage. Starting in July 2026, Iowa’s HF 2297 law requires all new residential builds to include passive mitigation pipes during construction.
A passive pipe does not guarantee safe levels, so you can review all the state-specific details in our guide to radon testing during an Iowa home sale.
Use the Retest Reminder Calculator
If you are unsure of your current timeline, use our digital reminder tool to calculate your next ideal window. This specific feature takes the guesswork out of property maintenance and keeps your family safe.
Our free radon retest reminder calculator analyzes the months since your last baseline test, whether an active system is running, and any recent structural changes. It immediately tells you whether to initiate a test right now or exactly how many months remain until your next deadline.
This provides a simple, foolproof way to put your next assessment officially on the calendar.
Which Test to Use
For routine two-year checks, a professional continuous monitor gives you a fast and highly detailed result in just 48 hours. If you want to understand your true year-round exposure, a long-term tracker lasting 90 days or more is the superior choice.
We strongly suggest comparing your exact options in short-term vs. long-term radon tests.
Here is a quick breakdown of your primary choices:
- Continuous Digital Monitors: Best for quick real estate transactions and precise 48-hour snapshots.
- Short-Term Charcoal Kits: An affordable first step for a rapid DIY baseline check.
- Long-Term Alpha Track Detectors: Best for capturing a 90-day average that accounts for extreme seasonal weather shifts.
If a recent assessment comes back above 4.0 pCi/L on a property that already has a mitigation fan, you must act quickly. Our dedicated system repair team can diagnose exactly what failed.
A simple phone call is often all it takes to start the troubleshooting process, so reach out today to secure your indoor air quality. By keeping track of exactly how often should you test for radon, you ensure a safe environment year after year.