How to Test for Radon to Keep You and Your Family Safe

how to test for radon

If you're buying a new home, you'll want to make sure that it is completely safe. Along with ensuring sturdy walls, safe stairs, and grounded appliances, you should know how to check for radon and other hidden hazards. Radon is not something that will show up on your home inspection, either. If you've already moved into your new home, checking for gas leaks, mold, and radon is one of your first steps to ensuring the health of your family.

The truth is that the air in a building can have no smell at all and still be quite dangerous. There are several substances that can permeate the air that are toxic for your health, including radon. And with many of them, you won't realize the danger until the effects have already started. That's why is why it is extremely helpful to learn how to test for radon and to apply this knowledge. Luckily, testing for radon is quite simple, not to mention well worth the effort.

What is Radon?

Radon is an invisible and radioactive gas. It is formed in the Earth's crust and is a part of the air everyone breathes. In the periodic table, it has the symbol Rn and Atomic Number 86. It is the heaviest known gas, with nine times the density of air. Classified as a noble gas, it's colorless and chemically unreactive -- it's the product of the decay of radium.

Radon was discovered by Ernest Rutherford and Ernst Dorn in 1899 and 1900, respectively, Rutherford discovered the alpha radiation, and Dorn discovered that radon was the gas being released by radium. It has no color, smell, or appearance.

Where radon can be found

Radon typically comes from the rocks and soil below the foundation of buildings. These rocks and soil have traces of uranium within. The uranium breaks down over long periods, forming other elements in the process of radioactive decay. One of these elements is radon. When radon decays, it emits an alpha particle, which is a form of radiation.

Radon can enter a building by rising through cracks in the foundation. It can also enter through sinks, showers, and hot water tanks. It will typically build up the most in the lowest levels of buildings. There are some buildings with high radon levels in upper floors as well, however.

This could be due to natural updraft or artificial ventilation. However, given that the lower floors are closer to the source, anyone who tells you how to test for radon will likely tell you that you should start by testing radon levels on the lowest floor possible.

Why radon can be dangerous

People have probably told you from childhood that smoking is dangerous, right?

The main reason for this is that smoking will heavily predispose you to lung cancer. What you likely haven't heard, though, is that radon is likely to cause lung cancer as well. Radon is the number one cause of lung cancer among non-smokers. In the United States alone, there are about 21,000 people who die from lung cancer due to radon exposure.

This is why it is so critical to know how to test for radon.

How radon works its poisonous magic

The alpha particles that radon emits can be toxic. They can't penetrate your skin, but you can inhale and ingest them. When radon and alpha particles are inhaled, they can damage the DNA of your cells. This is particularly true of the very sensitive tissue cells of your lungs. When these alpha particles come into contact with the DNA in these cells, they can damage the DNA blueprint of the cells. These cells will then replicate; if the DNA is altered, this can lead to cancer.

If the concentration of radon in your air is very low, you likely don't have to worry. Your cells have a DNA repair system that protects them from low levels of radiation. There are low levels of radon in the outside air, for example. However, as long as the concentration stays low, your cells will likely repair any alterations to your DNA. It's when the radon levels become high that you might have something to worry about and need to learn about how to test for radon.

Why it's important to test for radon

It is a good idea to know how to test for radon in any building. Whether it is your workplace or your home, you do not want to be inhaling any more radon than necessary. Radon has been found in buildings all over the U.S. There is no building that is immune. Radon can be present in homes with or without basements, well-insulated and drafty homes, old and new homes, et cetera.

In fact, modern homes are more susceptible to radon exposure than homes of the past. This is because they are generally well-insulated and energy-efficient. As such, they become traps for radon once the radon is inside.

Your risk for developing lung cancer is even higher if you are a smoker. Whatever your radon levels and the average amount of risk that they pose, this risk will be even higher if it is compounded by a smoking habit.

When you should test for radon

You should test for radon anytime you suspect that there may be higher-than-acceptable levels of this gas in your home. However, there are customary situations when you are expected to exercise knowledge of how to test for radon.

One of these is when you are buying a home. You should ask the seller for his or her radon test results. If the seller has not tested the home, you should have it tested yourself.

If you're selling your home, professionals would recommend that you know how to test for radon and do so before putting your home on the market. Being able to prove low radon levels in your home will be a positive selling point.

Overall, even if you are not in either of these situations, you should check radon levels a minimum of twice each year. Even if you had good results last year, there are many factors that can cause these levels to change over time. Seasonal influences, construction on the home, and your own living patterns are some examples. If you are going to be spending more time in the basement, for example, knowing how to test for radon becomes that much more important.

Radon Test Results: What They Mean

The average indoor radon level is approximately 1.3 pCi/L (picoCuries per liter of air). This is somewhat higher than the average outdoor radon level, which is about 0.4 pCi/L. The U.S. Congress has created a goal of making average indoor radon levels no higher than outdoor levels. While this is unrealistic at the time for many homes, it is possible to reduce levels to 2 pCi/L and under.

When you learn how to test for radon, you should also understand the results. A radon level of 4 pCi/L is too high and poses a significant risk. In that case, you should work to lower the levels. However, you should also consider taking action if the level is between 2 and 4 pCi/L.

How to Test for Radon: The Steps

If you want to know how to test for radon, rest assured that the process is quite simple. However, there are a few things that you should know about the major categories of radon tests. You can get either a short term test or a long term test. What you should choose depends largely on how urgently you need results.

Short-term tests

Short-term tests are a good option if you need quick results. Generally, they will be in your home measuring the radon levels for between 2 and 90 days. It would likely make results more precise if you have two testing devices collecting data at the same time. It would also be a good idea to do one short-term test after another so that you get readings over a longer period.

Long-term tests

Long-term tests will remain in the building for over 90 days. These are more accurate when telling you the actual average radon levels in your home. If you want to confirm initial results from a short term test, you may want to use a long-term test.

Steps for DIY radon testing

The specific steps will vary slightly depending on the type of radon testing device. However, for the most part, the steps are fairly universal when navigating how to test for radon.

1. Purchase a testing kit.

There are many different kinds of affordable radon test kits. You may want to check with your state public health department to see if you qualify for a free or reduced-price kit.

You can get either a short-term or long-term test. Keep in mind that with a long term test, it is best to involve the professionals. You need to make sure that whatever test kit you get, it meets the requirements of the Environmental Protection Agency.

2. Close windows and doors.

Closed windows and door

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You will need to close any windows and doors at least 12 hours before the commencement of testing. Keep them closed throughout testing as well. This way, you can get an accurate reading on the air in your home.

Make sure that you wait for relatively calm weather to conduct testing. The results are unlikely to be representative of normal circumstances if you do the testing when it is very windy or stormy. You can keep A/C and heating systems running while testing is going on. However, don't operate any machines that bring in air from the outside, such as fans.

3. Find the right spot.

Place your radon test kit in the lowest level of the building in which you spend a lot of time. Choose a room that you use regularly. However, you should avoid the kitchen and bathroom, as the results could be affected by various fumes and humidity in those areas. Put the kit a minimum of 20 inches above the ground, away from drafts, humidity, high heat, and exterior walls.

4. Leave the kit in place.

Follow the instructions that correspond to your specific kit. Leave the materials in place for the specified time period.

5. Collect and mail the test material.

Once the testing has been carried out through the specified time frame, reseal all necessary materials and mail them to the lab that is specified on the packaging. Send the materials immediately; you should not wait longer than a day or two. You should get your results back within a few weeks.

If the level is high enough to be of concern, you can repeat the short-term test or conduct a long-term test.

Alternative Options When Testing for Radon


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If you don't feel that you can learn how to test for radon on your own, there are other options. You can use an electronic monitor, or you can get a professional to test your home for you.

Using an electronic radon monitor

Typically, these electronic radon monitors are used by professionals. Most of the time, professionals use them in conjunction with more traditional methods, although you don't necessarily need to do this in your home. You place them face up on a flat surface, making sure not to block the ventilation slots on the device. These detectors will give you a continuous reading of the radon levels in the structure. You can easily see these readings on a digital display.

One major advantage is that you don't need to send any materials away to a lab to get readings. You'll get your readings just by looking at the display on the device. It will be possible to get results immediately after the testing is done. However, you should keep in mind that these detectors are very expensive. Some of these units can be in the neighborhood of $1,000 or more.

Hiring a professional

Another alternative to learning how to test for radon is to simply hire a qualified radon tester to do the job for you. You can email an online training program or contact your state radon office. Then, you can get a list of qualified testers.

This will be a more expensive option than doing it yourself. However, if you're afraid that you can't do it properly yourself, it will give you peace of mind to find someone that you know can. Additionally, if you are doing long term radon testing, you should have a professional at least monitor the job, if not perform it themselves.

Another advantage of hiring a professional will be that the testing team will likely recommend or even provide a solution. If radon levels are too high, they can bring in an experienced crew to solve the problem.

What To Do if Radon Levels Are Too High


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Considering the health implications of high radon levels, you should definitely address the problem if it exists. There is no use in learning how to test for radon if you don't take measures to mitigate a radon problem.


There are several repairs that you can do to hopefully lower radon levels in your home. If your levels are high, around 4 pCi/L, it is unlikely that this will be sufficient. However, they may make the difference if your levels are only slightly elevated. They will also be likely to make other methods of radon reduction more effective.

One thing that you can do is seal concrete. However, according to the EPA, this is usually only a temporary solution.

You can also cover the soil in any crawl spaces with polyurethane plastic sheeting that is tightly bound to the walls. It should have a minimum thickness of 6 millimeters. Also, use polyurethane caulk on any construction joints, cracks in the foundation, and other openings.

Radon mitigation systems

Before you try to implement a radon mitigation system yourself, you should consult with a radon mitigation contractor. Based on your location and the foundation of your home, they'll be able to make a recommendation as to what kind of radon control system would be most effective for you.

Radon mitigation systems can cost between a few hundred and a few thousand dollars. It depends on the specifics of the situation. Basically, the system will serve to ventilate your home; it will use PVC piping and a fan to draw radon from the soil directly out of your home rather than into it.

Are You Ready to Test Your Home for Radon?


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After everything you have just learned, hopefully, you are! If you don't feel that you have mastered the ins-and-outs of how to test for radon, you can always hire a professional.

However, you can likely do it yourself. It is mostly a matter of following the directions in the basic process and the specific directions on the package. The most important thing is that you take the process seriously, as you don't want high radon levels in your home. You want to make sure that the air in your home is clean and does not have a high concentration of radon and alpha particles.

The last thing that you want is to put yourself and your entire family at risk by breathing contaminated air! Have you ever performed a radon test in your home? Tell us about your results in the comments below.


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