Radon In Our House | What We Did

Update: Follow-up Test

We did another Radon test in February 2016. The result was good. It was 0.6 pCi/L. Well below the action level of 4.0 pCi/L.

The purpose of this post is to inform, not frighten. Thoughts of radon gas in the home conjure up fear in many people. Reading to learn about it can be challenging. There are very many stories, reports, publications, companies, and anecdotes. Making good sense out of them is difficult. It seemed important to document our story to help others have a clearer idea of the correct information so they can make well-informed decisions.

In the spring of 2014, I attended three Mini-Med School sessions for the public offered by the U of IA College of Medicine, about research they are doing on cancer. Presenters told of their efforts to understand the disease, decode its behavior, and how the public benefits from their research. A presenter the second week spoke about lung cancer. Because we live in Iowa, the subject of radon infiltration into homes was part of the discussion. Radon is recognized as the second leading cause of lung cancer behind smoking. Iowa has the highest levels of radon of all the states. Every county in Iowa has levels which exceed the recommended maximum.

The Environmental Protection Agency citizen guide says the maximum level should be 4 pCi/L (pico-Curies per liter of air). The pCi/L is a unit of measure of radioactive concentration in a sample of air. Readings above 4 pCi/L should have mitigation done to reduce it. The average level for the nation for outside air is 0.4 pCi/L. It might be as high as 0.75 pCi/L, depending on where you live. The problem with radon is how it seeps from the ground, infiltrates through the slab and walls of the foundation, and accumulates in dwellings to levels that might exceed current health standards.

This map predicts the likelihood that dwellings in these zones will have a particular value of radon when tested. It does not state that all dwellings will have those values. It is predictive of the potential. Red zones predict a value higher than 4 pCi/L. All of Iowa is a red zone.

Red Zone 1 (>4 pCi/L) — Orange Zone 2 (2 to 4 pCi/L) — Yellow Zone 3 (<2 pCi/L)

Following the university sessions, I felt it was important to test our house for radon level. I don’t spend a lot of time in the lower level where radon tends to be the highest amounts. But, my wife Melanie in IA does. She is a quilter. Her fabrics, sewing machines, and projects are all on the lower level. She deserves a safe environment. Plus, she was raised in a house with a lot of second-hand smoke. That raises her risk factor.

Our Test Results

I bought a First Alert radon test kit from the hardware store. There are several brands available. The kit cost about $12 and included the cost of getting the test results. I followed the directions and placed the package on a work base in the area Melanie uses. It was left there undisturbed for a few days as directed. Afterward, it was placed in the mailer with details of the dates and times it had been left exposed. In a few days, I received an email notice with the results. The reading was 13.8 pCi/L, more than 3x the recommended maximum.

That was a disturbing result. I read a lot of literature and reviewed the information received in the university class. Two weeks later I bought two more kits for a repeat test of the same location and a test of the utility room area behind the wall of her work area. This time the reading was 14.5 pCi/L in her work area. The utility room was 16.6 pCi/L. We decided to get in touch with a certified mitigation expert to get an estimate of the cost to bring those values down to acceptable levels.

Risk Analysis

According to the EPA Citizen’s Guide, the risks of developing lung cancer can be compared to other risks in these informative charts. The charts assume 1000 people are exposed for a lifetime at some particular radon levels. For non-smokers like us, using our radon test results of about 14 pCi/L, a lifetime of exposure at that level is more than 20x the risk of dying in a home fire. According to the National Cancer Institute

Cigarette smoking is the most common cause of lung cancer. Radon represents a far smaller risk for this disease, but it is the second leading cause of lung cancer in the United States. Scientists estimate that 15,000 to 22,000 lung cancer deaths in the United States each year are related to radon.

Exposure to the combination of radon gas and cigarette smoke creates a greater risk of lung cancer than exposure to either factor alone. The majority of radon-related cancer deaths occur among smokers. However, it is estimated that more than 10 percent of radon-related cancer deaths occur among nonsmokers.

Examine these charts and others yourself. Do the risk analysis for your own peace of mind. There is no guarantee of getting lung cancer. The purpose of this blog post is to inform, not frighten. Because the risk can be significantly reduced, we chose mitigation.

How Does Radon Cause Potential Harm?

Radon is a colorless, odorless gas. It doesn’t react with other chemicals or atoms. It is produced from the decay of naturally occurring uranium, which is radioactive. Uranium is found in small quantities in the soil, water, and rock of our surroundings. Some areas of the country, such as Iowa, have larger amounts of it. As the uranium decays, one of the products is the gas radon. The radon gas is also radioactive and will decay into other products. Half of the existing radon atoms will decay within 3.8 days. Half of those remaining will decay in 3.8 days. And, so on, decaying to smaller rates. New radon atoms are being introduced from the uranium decay in the ground below the dwelling to re-supply those that have decayed.

Radon gas is not the principle cause of harm. Products of radon decay, called progeny, are polonium, bismuth, and lead. Each of these is radioactive and a solid, not a gas. They can attach themselves to dust in the air and be breathed into the lungs where they might do damage. They can attach to the lining of the lungs and undergo their own radioactive decay. Half of those progeny will undergo alpha and beta decay within the next 30 minutes. Half of those remaining within the next 30 minutes, etc. decaying to smaller rates. All the while, you might be breathing in more radon gas from your room air to continue the decay process at a relatively steady rate.

When radon and their progeny decay, they emit high speed energetic alpha and beta particles to their surroundings. If they do so in the lungs, the surroundings are sensitive tissue cells of the lining of the lungs. The high speed alpha and beta particles can cause damage to the DNA of the tissue. Such damage may be the source of a tumor of lung cancer. There is no certainty. But, the risks are increased.

Mitigation Of Our House

The man who did our work is a local resident. He has done this work for 20 years and has an excellent reputation. He came to our house to assess the possible methods he might need to use to make our house safer. He answered our questions during his visit. A few days later he sent his estimate with three possible scenarios. Which he would use depended upon the underlying gravel layer beneath the concrete slab. They ranged from $1300 to $2000. Every house is different with unique challenges and costs. Prices will vary. We told him that price range was acceptable and to set a date to do the work.

Radon enters the living space through the slab, cracks, sump pump holes, water line entry points, … any spots where the tiny gas molecules can get through. Mitigation involves drilling a 4″ hole in the slab of concrete to attach a PVC pipe and motor that creates a low level of suction. That motor runs quietly and continuously to draw the radon gas to the 4″ hole where it is directed out through the roof to the outside. This prevents the radon from accumulating in the living space. It is a simple and effective method.

First, our technician needed to assess the gravel conditions under the slab of concrete. A bathtub in the lower level allowed him to see what was under the concrete. He cut a hole in a closet to access the tub piping. He established there was porous gravel below, which was a good sign which allowed him to use the least costly scenario. Then, he covered the hole with a ventilation grate.


Second, he drilled a 4″ hole in the slab in the back part of the utility area of our downstairs. There he temporarily attached the suction motor. Then, he went to a far corner of the lower level, pulled back some carpet, and drilled a pencil sized hole through the slab. He repeated that process in a closet of a bedroom. He turned on the suction motor and measured the amount of vacuum at the drilled holes. He established there was enough flow across the bed of gravel below the concrete slab to properly ventilate the radon gas out with the motor. He plugged the small holes and repaired the carpets. These are actual before and after of the carpet repair.


Third, some 4″ PVC pipe was sealed to the hole in the slab and directed up to the ceiling. An opening was located where the pipe could be directed into the garage in a convenient spot.


Fourth, the PVC pipe was sent up to the garage ceiling into the attic space. In the attic, the suction motor was installed and the exit was installed to the outside through the roofing. I have been in the garage several times with the door closed to listen for the motor. It is barely audible, quieter than a running refrigerator motor. We never hear it inside the house.


Follow-Up Testing

We conducted follow-up radon tests a week after the mitigation with two kits supplied by the installer. No payment was required from our installer before the final test results were received. Whether that is a common practice, we do not know. It did help us feel more secure that he was confident in his work and that we would be more protected than before.

It has been two weeks since our mitigation work was done. Email notices were received with the test results. Both said…..

07/15/14 ACTIVATED CHARCOAL RADON TEST #6508797 and #6508798

* Radon Test Results = < 0.3 pCi/L

* Test Started 07/07/14 at 7:00 am
* Test Ended 07/11/14 at 8:00 am

* Location Basement/Lower level Living Space


The US EPA action level for indoor radon is 4.0 pCi/L. Test results in this range (0.5 pCi/L or less) are, for all practical purposes, equivalent to the radon levels found in fresh air.

Exactly the kind of news we hoped to get. We feel our risk has been reduced. We are able to breathe easier today.

Another test was performed in late January 2015 after the house was closed up for several months. The results showed less than 1.3 pCi/L. This value is the average indoor reading for households. The system seems to be working well.

Links for more information…

Where You Live clickable map links information for U.S. states

Environmental Protection Agency citizen guide

Nation Cancer Institute radon risks

U of Iowa College of Public Health (pdf)

European Radon Map 2011

Canada FAQ

World Health Organization search results for ‘radon’



20 thoughts on “Radon In Our House | What We Did

  1. Very good, Jim. We too had a radon experience at our former house here in Joplin near the boundary between orange and yellow on your map. It had a basement in which we had a family room and when I read about radon I also bought a tester. That was somewhere around 1990 I think. In those days, testing was a much more lengthy process – I had to leave the device in place for several months. The results were just below the 4 pCi/L level. Because it was a basement there was no underlying gravel to tap into, so mitigation was not a simple option. Also, we only spent a couple of hours down there a day. (As I’m sure you know, radon is heavier than air and sinks to lower levels.) But it still worried me and I was glad to sell it in 2000. Our present house has a sealed crawl space.

    Your outline here is excellent advice for everyone. Radon is a huge health issue that goes largely ignored, a silent killer. I was personally sensitive to the danger because my father died of cancer at age 58. He smoked, but who knows how much other factors like radon might have contributed?


    • Thank you, Jim, for the details of your experience. Houses are different. The land they rest on is, too. There is not a single prescription of whether a house presents a radon problem. Since testing today is a relatively simple and inexpensive process, it ought to be done. It can offer peace of mind.

      In Iowa, houses need to be tested upon sale as part of the disclosure statements in the contract. Many buyers ask that mitigation be done if the numbers are high. That is part of the negotiations between buyer and seller.


      • Right, Jim. If I had my way I would be in favor of legislation making radon testing mandatory for all house sales in all the areas in red on your map. After all, they did that for the problem of lead paint and that was probably a smaller problem. It was even applied to rentals.

        Liked by 1 person

  2. Your last paragraph is important for home owners to know. If you test your home even years before you are selling you must disclose that fact at the time you seek to sell your home, regardless of whether you chose to install mitigation based on your use of the lower level space. The cost for installing a mitigation system is most often an expense the seller bears. Home sellers experience this as a surprise & the dollars they were hoping to net are less than expected. The negotiation often means the buyer walks away if the seller won’t install or pay for the mitigation by a reduction in sale price that had been negotiated.


    • I contacted our realtor about that issue. She said that, too. It is information that needs to be disclosed, like others on the disclosure statement forms.
      As a buyer, I want to know the condition and quality of the product. The seller is the one who has lived in it and knows the ‘secrets and quirks’ of the property.
      Disclose the truth, then negotiate what to do as an agreement.

      Thanks BJ for stopping by.


    • I didn’t intend to scare anyone with the post. The test is inexpensive. You might have other ways to change the air circulation and ventilation in nice weather.

      I hope you get low numbers if you test. Orange doesn’t mean you will test high.


  3. You are a very honest, smart man, JIM! Very informative writing and helpful for lots of people. Thank you!


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