The EPA and most State Health Departments urge that every home be tested for radon on the first level living area of the home. However they have fallen short in educating people about the importance of testing for radon on upper levels, which can have higher radon levels.
I’ve tested radon in hundreds of homes as a home inspector and radon mitigation contractor. The vast majority of those tests have been conducted in basements or the first floor of the home. On occasion however, I’ve done radon testing on multiple levels of the home simultaneously. Those test results have often shown the highest radon present in the uppermost level.
Many radon testing professionals and most homeowners never test above the first living level in a home. They have no idea if the radon level is higher on the second floor, because the general consensus is that the radon level is highest in the lowest level of the home.
Most professional radon testing is performed on the lowest living level of the home or a basement if present. That is what we are taught to do. In Central New York most radon tests are done in the basement, even if it is not a living area. So it is a common practice in Central New York, and many parts of the United States and Canada that most home inspectors will perform the radon test in the basement level even if it is not a living area, if that basement could be used for any type of activity, such as a workshop or laundry room, etc.
The reason behind this is that, it is is generally understood that radon, being a heavy gas, is highest in the lower level of the home. And I have found that this is generally true most of the time, but far from all the time. Testing for radon in the lowest livable area is a good start, but often testing for radon on upper levels can reveal an even higher radon level in an upper level of the home. Most people don’t realize the radon level can vary a lot from room to room and from one level to the next.
Over the years I have conducted radon tests on multiple levels of homes at the same time with some surprising results. In a newly constructed home a few years ago, we tested the basement, first floor and second floor during the winter, the house was closed up tight and forced air heating system was heating the home. The unfinished basement radon level was slightly above 4 pCi/L, the first floor was lower at just above 2 pCi.L and one of the second floor bedrooms tested at above 8 pCi/L. I have seen similar results in other homes, including my own 1820’s farmhouse which had radon level of 17 pCi/L in the unfinished, stone wall and dirt floor basement; 3 to 5 pCi/L on the first floor and 11 to 13 pCi/L in the upstairs bedrooms.
The type of home construction, the insulation and air sealing of the home, the time or season of year, the type of heating system all play a part in the radon levels in a home and can vary greatly from season to season as well as from floor to floor or even room to room. For these reasons it is not a bad idea to do a little extra testing for radon on upper levels, especially if you live in a high radon area, or have done one test already that indicates elevated radon on a lower level.
Radon is known to be a heavy gas. And not much radon testing has been conducted on upper levels of homes. For these reasons many realtors and radon professionals are not aware that radon can be higher on upper levels of homes so they often tell people that the radon levels are less in the upper levels. Many times that is true but not always. Please understand that the radon level can be significantly higher on an upper floor. Even if the radon level is lower on the first floor than say a basement radon level, it could be higher on the second floor. The only way to know is if you test.
Testing for radon on upper levels is important because for most people the amount of time spent in the home is much greater on the upper levels, especially the level of the bedroom(s). If the radon level is higher on an upper bedroom level it will usually mean greater exposure to high radon levels. Higher radon levels discovered by testing on upper levels may indicate the need for radon mitigation or reducing the radon that was not recommended or realized with prior test(s) at a lower level.
If you have experienced higher radon levels on upper floors in your home, please share your results on testing for radon on upper levels in the comments section below. Thanks for reading.
Our basement is showing radon levels of 17. ( 1 week test) I just started testing our ground level and it’s showing that we are at a 9. It’s only the first day of testing so maybe it is from all the rain we’ve have but I was pretty shocked to find high levels of radon at our floor level. Our home was built in 1908. We have lived here for 12 years so I am concerned about our health now. Hopefully we will show lower levels the longer we test.
That is fairly typical, the first floor radon level, above a basement is typically about half as high as the basement radon level, rough average.
Good writeup. You’re right that radon is a heavy gas… please consider that elevated radon levels in upper levels of the home are likely caused by waterborne radon released to the air during use (e.g., showers, laundry, etc.). Additionally, radon levels fluctuate – sometime dramatically: in our basement, the first 6-month test (Jan-Jun) averaged less than 2 pCi/L and the second 6-month test (Jul-Dec) averaged over 7 pCi/L.
In order for radon in water like a shower to significantly raise the indoor radon level it would have to be at extremely high levels in the water which is not the case in most of the country. I do know Main has some radon in water levels in the + millions of pCi/L and that can make a difference but that is quite rare in most states. Radon in water must be relatively high (from about 8,000 to 12,000 pCi/L) compared to radon in the air (+ 4 pCi/L), before it has any impact on raised levels in the home.
I had a radon mitigation system put in my sump pump due to high levels found in the basement. After this was done I decided to check the rest of the house after the retest in the basement. The rest of the house still wasn’t that bad but it was higher than the results from the basement and the further I went away from the mitigation system the higher it got the end result being my master bedroom was the very worst place in the house.
Now I am trying to ask the people who put the medication system and how I can get the numbers down more in my master bedroom. They are telling me those numbers don’t matter that all that matters is the basement numbers. And yes the level is still low in the bedroom but I have Lyme disease and I am having a very hard time and have not been able to sleep in the bedroom since I’ve moved into the home. So now I am very confused as to what I need to do but something is very wrong in that bedroom I have not been able to sleep in there for the six months I’ve lived here. So I sleep on the floor in the living room.
I would contact another radon mitigation company, the radon level that is most important is the room(s) you spend the most time in. The EPA says the testing should be done on the first level living area. If you do not live in or spend much time in the basement the first floor is where the testing should be done. The radon mitigation system should be able to be modified to address the higher level in bedroom. The EPA says even if the radon level is below 4.0 you may want to consider mitigation if it is above 2 pCi/L in an area where you spend a lot of time.
Hello I’m messaging from Maryland .
Recently moved into a rancher with a finished basement it was built in the 50’s. Before moving in we had a radon test done and Levels in the basement were almost 5 so we had a mitigation system installed. I bought a monitor and been testing different rooms found basement levels have been mostly below 1 but upstairs has been above 1 and almost at 3 . I’m very concerned. Is it possible the vent is not high enough up above the roof ? Could the radon be going into the attic and making its way back into the house? What levels are expected after mitigation? Is there any way to completely remove it? Or will there always be some amount of radon in our home? Not very happy right now.
It is very highly unlikely that any radon is coming in above the roof or from outside anywhere. In Canada the recommendation, due to cold weather and the vent pipes icing up is to vent the radon at ground level like a dryer vent and it is perfectly safe for the most part because the radon disperses so quickly when in the outside air. Your issue has to do with how air is moving inside the house, possibly the HVAC system. It can be improved upon but you may need to bring in a professional preferably with radon and air handling – indoor air quality experience.
Those are really pretty good numbers. It is quite difficult, almost impossible for radon to re-enter a home, it disperses very quickly. Look at the Canadian government recommend radon mitigation method, they vent out at ground level next to and under windows. It is really a non issue for the “most” part. You can expect radon levels below 4.0 pCi/L. If you are willing to pay extra money they can try to get it lower, use a bigger fan to move for air for example, but some homes can be quite difficult to get much below 4. Many many factors involved. It is worth a try to get it lower, but realize there are no valid guarantees to get it much below 4 or below 2. You may want to conduct a test in your back yard in the open air and see what you are up against. Especially if the outside air radon level is above what it is in the home.
Install house airexchange system, it is may cost you few gran but that is the option. Another manual temediation- have your haiuse ventilated naturally by opening windows and doors frequently and for longer period. The half- life of the radon is 3 days. So i would do it at least once a two days. It will lower the risk to the health.
In my house we had time radon rised up to 56 on upper levels, and to 3 pic/l in the basement, i still do not have any explanation of such dramatical difference, except in wall drafts and tunnel vortexex
I would say that is very unusual. Not sure what could cause that. I did see a fireplace in a second story master bedroom once that had high levels of radon coming from the bricks in the fireplace, uranium – radium in the building materials is a possibility in some cases.
We also live in an old farmhouse with stone basement in radon-rich Maryland. We can get the first floor reading down under 2 with all the windows open (otherwise run 6-10), but the second floor is always higher, and opening the windows up there seems to make it worse. I’m thinking the return vents into the attic space are drawing the radon up from the basement through the house? My next step is to cover these returns and see if we can get the radon lowered. Thoughts?
Might help. Did you mitigate the basement? That would stop almost all of the radon from even getting into the house in the first place.
I installed some mini splits 8-9 years ago and was told by the installer that I could shut down my air exchanger (house is 15 years old). Not knowing any better and not questioning enough at the time, I came to find out that is not the case as mini splits do not use outside air. That being said, I have had an air exchanger shut down probably 8 years but started it up again last week. Obviously there are still air exchange through the opening of doors window and what not. I just hope I have not caused any health issues to my wife and I. I have been testing for Radon during the past week using and Airthings monitor as I have learned more about it. Our levels are averaging at 30 bq/m3 which is very good. However I am worried about what kind of Radon levels I have had over the past years with the air exchanger turned off, especially during winter months. From what I have read, they were probably worst. Were they at a toxic level? Who knows…I really feel bad about this.
I think you are on the right track. The basement is most likely very drafty with lots of air exchange going on and then heat rises taking the radon up and if the attic is air sealed it becomes trapped in the upper level.
Sorry to hear that. That was very unprofessional and unethical and just plain wrong of that company. It makes no sense at all that they would say it only matters what the basement level is, on the contrary, it matters most where you spend the most time which for most people is their bedrooms. They just don’t want to do any extra work or to be bothered to spend any more time since they made their money on what they did.
I have 3.2 to 3.78 radon level on second floor bedroom in a 4000+ sq feet home with finished basement. This is my very first test in past 24 hours of reading.
Now testing each bedroom with a monitor and after 7 days they are mostly showing between 1 and 2. I know this is low compared to some levels I been reading about here but I really would prefer 0 is that at all possible?
The lower the better, but below 2 is quite good and sometimes better than the outdoor air.
Test outside. See what the outdoor air is. To get 0 you may need to move to another state. Any radon below 2.0 is quite low. Your levels are lower than what a lot of places have in the outside air.
Do a long term test for a week or more to get a better more accurate result.
Initially my basement tested a little over 9 and a bedroom upstairs was about 6.1.. we put the mitigation system in and the basement average is below 1 but upstairs is higher at 1.4. I am wondering why and if the mitigation system could be modified to get better numbers upstairs, which is where it matters most.
Most radon systems can be improved upon quite easily, usually increasing the size of the fan depending on the type of subsoil present. If you have dry gravel below the basement floor a higher volume fan should improve, or if you have wet sand or clay soil a more powerful fan with higher suction power would help improve. Also adding additional suction point or sometimes a fresh air make up vent if the house has any negative pressure issues or backdrafting going on when gas appliances are running.
Anything below 2 is pretty darn good. Most likely can be dealt with by balancing air flows in the home, the HVAC system and fresh air ventilation and insulation and air sealing.
Hello I bought two Airthings that I have located in my hallway on the upper floor of my house and in my boy’s bedroom, both always shows different numbers or radon but the numbers never went over 0.6 pCi/L as short term, I have to say I don’t know anything about radon but all what I had read is driving me a little crazy and I want to move, does it really exist a house with 0.00 pCi/L level? Thanks
At 0.6 radon that is almost zero and very likely less that the outdoor air, maybe do a test outside about 2 feet above the ground. Anything below 2.0 is considered very good in most situations. The average outdoor radon in the USA is about 0.4 pCi/L and you must consider that most of the US has very little radon well below 0.4 pCi/L. So that means that in many parts of the country the outdoor radon level is significantly higher than 0.4 pCi/L. Some areas of central NY where I live well over half the homes have high radon well above 4.0 pCi/L so radon mitigation systems are a way of life and considered a home improvement, they should be considered as a capital improvement, increasing the value of the home and quality of life.
0.6 pCi/L of radon is pretty darn close to 0.0. The average outdoor radon in the USA is reported to be 0.4 pCi/L. Many areas the outdoor radon is much higher than 0.4 pCi/L, I have tested it as high as 10.0 pCi/L about 3 feet above the lawn in a back yard. In my opinion, You should be very pleased with any level below 1.0 pCi/L.
Just bought a continuous radon monitor after short term test showed basement at 15 pcu/l. Main floor was 14 and upstairs on 2nd floor was 17. I just sealed off the cold air return inlet on the basement furnace as I suspect that it was pulling in radon basement air and sending it through the entire house. Have not opened all the windows yet to ventilate entire house.
Can’t say for sure. Most of the higher levels of radon in upper floors I have seen is in the heating season and due to highly insulated attics in relation to comparatively drafty basements, air moves up through house and is trapped in upper level.
That’s a good place to start.
I am wondering about split level homes with half basements. I have a 1,946 sq ft home that has 4 levels. The basement only goes under half of the house, so not only is there dirt beneath the basement floor for radon to come through, but there is dirt under the rooms that are the next level up and to the right that do not have any of the basement under it – just dirt going up to it them that is on the other side of the basement wall. Can a basement radon mitigation system actually get the radon that is rising up a level on the other side of the basement wall or is a second system needed one level up?
Thanks for the question, the only way to know for sure is to test each level / area. Doing the tests simultaneously would be best because the radon level can vary alot in some homes from day to day or week to week etc.
We just got tests back for our basement at 14 pCi/L. Our bedrooms and my two year old’s play room are in our basement so we spend a lot of time there. We’ve only been living there for 1.5 years but I’m so concerned now. We are working on remediation but now I’m trying to figure out if we should be sleeping in the upstairs bedrooms. But that wasn’t tested and based on your article now I’m just not sure.
In the great majority of homes radon level is higher in the lower, basement level of the home. The only way to know for sure is to do the testing. Home radon monitors are readily available online for less than the cost of hiring a professional to do a single test.
Sometimes one suction point from a single system will do the trick, it is a good place to start, then if needed you can add a second suction point that ties into the upper level by going through the lower level wall to tap into the soil under the upper level floor, two suction points tied together into a single fan. One radon fan can actually handle several suction points if it is sized right, and average radon fan can usually handle two or three suction points depending on the soil density.
We are about to mitigate radon in our 22 year old home. Recently a Airthings Radon detector indicated 24 pCi/L in the basement. With the basement windows open we are now averaging 1.6 pCi/L. Our 2nd floor is at the same level or less BUT our main/first floor living space is consistently higher than the basement levels, sometimes almost double (though now under 4 pCi/L since the basement windows are open). We had an HVAC specialist balance our system so that does not appear to be the problem. I am worried that even after getting active mitigation in the basement (they guarantee under 4 pCi/L but most of the time get under 2) our main living space will remain higher – potentially almost 4 pCi?L. Any thoughts or suggestions?
With the windows all open the radon can act much different that when window are closed. I would get the system installed and it should get rid of the vast majority of the radon before it gets through the basement floor. Right now the radon is flowing up through the basement floor and then out the windows.
5 years ago my mother-in-law passed away from non-smoker lung cancer. With my husband being a former smoker, I had someone test Radon on my first floor and the average 48 hours was 0.5. In 2018 my mother got lung cancer (non-smoker) and passed away, and this year my sister was also diagnosed with lung cancer. I got really concerned and I purchased a monitor to test. For the first floor it went up to 0.8 sometimes. I brought it upstairs in my bedroom, it’s about twice as high, sometimes 1.6. Even though it’s not considered high based on EPA’s standard, but because of family history, and my husband a former smoker, I’ve been feeling a lot of anxiety. I constantly check the reading and my anxiety level just goes up and down and I cannot sleep well at night when the reading is high. I do not have peace.
My first and second floors have separate HVAC systems. We have high ceiling so radon get upstairs easily I think. The 2nd floor return is down the hallway on the ceiling which has been taped over by me. I shut the bedroom door always and stuffed plastic bags at the bottom to prevent air going in. It seems I did a pretty good job to seal the room but Radon level still goes up. Yesterday we turned on the 1st floor heater and the 2nd floor reading just went right up. Later I opened the 2nd floor bedroom window and it just wouldn’t make much difference. There were situations I used a Varnado fan on the floor just try to blow Radon out of the room but the reading wouldn’t change a bit. I did all kinds of experiment and I could not find a way to bring it down and I’m very frustrated.
There are 5 narrow (2mm) but long cracks in the garage and one or two may extend and run through the house slab. I’m not sure if sealing those cracks will improve the situation. I was trying to contact a State certified mitigator who is located closer to my house but no one answers. With the wild fire burning causing really bad outdoor air quality, and the indoor is filled with radon, I’m pretty depressed. Could someone please give me some advise. Thank you very much!
Radon levels below 2.0 pCi/L are really quite low and often lower than what is in the outdoor air. The original tests done that showed elevated levels of lung cancer in people exposed to high radon levels were uranium miners deep underground in horrible air conditions, very dusty, exhaust fumes and the radon levels were above 1 million pCi/L and well over 90 percent of the miners were chain smokers. Yes they had higher levels of lung cancer than the general population, but they could not say it was due to radon. Possible in part but those conditions are far from what is in most homes.
I am also experiencing higher radon levels on the upper level. I have an AirThings monitor on each floor. One is upright in a holder and the other lays flat. Could that make a difference in the way the monitor is recording the radon levels ? Also, is it the average long term radon that needs to be watched and not the day to day fluctuations?
The position of that monitor does not matter much, what does matter is the location, it should be central in the room, dresser height or higher, and NOT near any air movement, fans, dehumidifiers or heat/AC ducts. And yes the long term reading are the most accurate and most important to evaluate risk and what is going on.
The radon is highest in 2 bedrooms on the main floor. Even higher levels than the basement. These two bedrooms have rock/brick-work on the exterior wall. The master bdrm radon level is the lowest in the house and doesn’t have and brick-work. Could this brick be a contributing factor
Possibly, radon can be in brick and rock. But most likely not.
This is the case in my house. I think I know why too – in the basement and living room our return air grates are on low on the wall, near the floor. But in the bedrooms they are high, close to the ceiling. As radon is circulating through our home, it is being sucked in from basement low vents and then can’t escape through the high returns in the upper floors.
Ours has the same problem; bedroom radon higher than basement. I think the issue is that our return vents in bedroom are close to ceiling, while at lower level they are near floor. So the radon that enters the bedroom has a harder time existing through our air returns, even though we have an ERV.
Also if the air is blowing on or near the test machine or kit it will give you a false high reading. Try to do the test where there is no air blowing around.
Are higher radon levels in the upper living areas due to the HVAC sucking up the air from the basement and pushing it through the house? Then the air has nowhere to go so it essentially just stays there and accumulates?? If this is the case, after mitigation, is there anything else that can be done besides opening windows in the winter?
That is part of what is going on but there are a lot more things going on. Heat rises, the thermal stack effect, lost depends on how well the house is insulated and air sealed in the attic, balancing of the HVAC system, etc. etc. I can’t say without actually seeing the home.