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.
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.
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.
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.
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.
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.
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, Harvey
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.