1. What is radon?

Radon is a colorless, odorless, tasteless, gas that is carcinogenic.  It is naturally occurring and is present in low levels in the air we breathe outdoors (typically around 0.4 pCi/L).  The EPA projects that indoor radon levels may be between 1.3 pCi/L and 4.0 pCi/L depending on your home.

2. How does radon enter my home?

Radon's primary entry point is through the soil.  The amount of radon in the soil depends upon the soil chemistry and varies among houses and may be affected by weather, soil moisture and porosity, home construction, foundation types, and home pressure.  Radon levels vary by region but are present in all states


2.1 Some entry points into your home:

● Cracks in floors or walls of the foundation

● Gaps in suspended floors

● Openings around sump pumps and drains

● Wall cavities

● Construction joints

● Gaps around service pipes or wires

● Crawl spaces

● The water supply (Radon can affect bodies of water, specifically ground water)

3.   Will my neighbor's radon measurement indicate whether I have a radon problem?

No.   Radon levels vary from house to house. The only way to know if you have a radon problem is to conduct a test.  "...Your home can have elevated levels of radon while your neighbor's home does not. Testing is the only way to determine if you have a problem. Radon testing is easy and inexpensive, and it could save your life. Thousands of lung cancer deaths could be avoided each year if homes with elevated radon underwent changes to reduce radon pollution." [3] 

4.   I live in a newer home built with radon resistant new construction (RRNC).  Do I need to test for radon? 

Yes.  Effective June 1, 2013 the Illinois passed the NUCLEAR SAFETY (420 ILCS 52/), commonly known as the Radon Resistant Construction Act.  This new law mandates that any new construction (original construction of a single-family home or a dwelling containing two or fewer apartments, condominiums, or town houses) must have either an active or passive mitigation system installed.  Active mitigation systems, also known as active soil depressurization "ASD" offers many options to control radon levels.  Active mitigation systems involve mechanically driven soil depressurization, including sub-slab depressurization (SSD), drain tile depressurization (DTD), block wall depressurization (BWD), and sub-membrane depressurization (SMD).

Alternatively, these properties may install a "passive new construction pipe."  This means a pipe is installed in new construction that relies solely on the convective flow of air upward for soil gas depressurization,  this may consist of multiple pipes routed through conditioned space from below the foundation to above the roof.  Regardless of the system incorporated into your home; all homes are equally susceptible to the exposure of radon because of it is a natural gas.  The only way to identify if your home has high levels of radon is to have, you’re a radon measurement performed.


5.   What if the first measurement returns radon levels higher than 4.0 pCi/L?

If your first measurement results are four picocuries per liter or higher, it is recommended that you perform a follow-up measurement to verify the reading. If a second measurement returns results greater than four picocuries per liter, it is advised by both the Illinois Emergency Management Agency, Division of Nuclear Safety (IEMA) and the Environmental Protection Agency that you mitigate your home (take corrective actions to lower the radon levels).  By process of radon mitigation, the unsafe radon levels will be reduced to safe levels.


6.   Are Sellers required to disclose radon measurements?

Yes.  The Illinois Radon Awareness Act and the Illinois Real Property Disclosure Act require that a seller of a home disclose information if aware of unsafe concentrations of radon in the home.  The acts do not require that testing or remediation work be conducted. 


7.  When should I get my home tested for Radon?

If you are buying a house, the US EPA recommends including the radon test for EVERY real estate transaction. Even if your previous test result showed safe amounts you may want to test again sometime in the future. 


7.1    When buying a house:

If you are home buyer, the United States Environmental Protection Agency (U.S. E.P.A.) recommends including the radon test for every real estate transaction. The Illinois Emergency Management Agency, Department of Nuclear Safety (IEMA) recommends radon measurements be performed every two years (or sooner if construction is performed on the building).


7.2  Follow - up Measurements:

Follow-up measurements are performed to confirm and characterize elevated radon concentrations that were previously identified in a building.   Follow-up measurements are not required in real estate transaction.

An educated consumer is the best consumer.  Schedule a radon measurement to get the air quality assessment that is vital to your health!


 7.3  Pre- and Post- mitigation:

Pre-mitigation:  When presented a high radon report, from either a previous measurement or another company; it is important to validate the results you have been presented. Radon can be a sticking point in some real estate transactions and having accurate information  is priceless.

In situations where an existing radon concentration is known and reported high, it is common to have a follow-up measurement by a second company.


7.3.1   Post-mitigation:

  • Post-mitigation measurements are performed to ensure the newly installed radon system is working correctly and determine system efficacy.  

  • Post-mitigation measurements shall not be  performed any sooner than 24 hours or later than 30 days after the successful installation and activation of the radon mitigation system (per IEMA)

8. Operation of mitigation systems during radon measurement

    The mitigation system shall be operated normally and continuously during the entire measurement period

9.  I have a new home with no cracks or other openings, so why should I test for radon?

As a gas, radon can enter through small cracks that you may not even see.  Radon enters through finished and unfinished basements, crawlspaces, slab foundations, construction joints, unaerated water supply, and through the sump pits, floor drains and vents of both new and existing homes and buildings.


10.  How can radon from water enter my home?

Dwellings that are supplied with private well water for drinking, cooking, bathing or operating the dishwashing machine enable radon to diffuse into the air when the water is run.  The best way to protect yourself from any radon in well water is by aeration.


11.  If radon is a health hazard, what are they symptoms of exposure?
Just as you can not see it, smell it or taste it, radon provides no warning that it is harming your health.  There are no rashes, head aches or fevers.  Radon causes lung cancer, which often present no symptoms until it is advanced.  The only way to be safe from radon-related lung cancer is to test for radon and have the radon mitigated if the level is above 4.0 pCi/L.

12.  What Illinois law require radon testing in day care centers? 

August 17, 2012, Governor Pat Quinn enacted new legislature, calling for non-residential day care centers to have mandatory radon measurements performed on their facility by a licensed radon professional.


13.  How do these new laws affect day care providers?

Effective January 1, 2013, licensed day care centers, licensed day care homes, and licensed group day care homes shall have the facility tested for radon at least once every 3 years.


The Child Care Act of 1969 (225 ILCS10) Section 5.8 states that the facility must post their current radon measurement next to the Department issued license, and that copies must be provided to parents or guardians upon request.


Effective January 1, 2014, as part of the initial or renewal application of a license for a day care centers, day care homes, and group day care homes, the Department of Children and Family Services (DCFS) shall require proof the facility has been tested within the last 3 years for radon according to rules by the Illinois Emergency Management Agency, Department of Nuclear Safety (IEMA).


* The report of the most current  radon measurement shall be posted in the facility next to the license issued by the Department.  Copies of the report shall be provided to parents or guardians upon request.


14.  What if my day care center measurement result is greater than 4.0 picocuries per liter (pCi/L)?

The results must be posted according to the Child Care Act of 1969 [above]..." and current radon measurement next to the Department issued license, making copies of the radon report available to parents or guardians upon request."


However,  day care centers are not required to mitigate the building if they are found to have high levels of radon!  ASK your day care provider if their building is radon safe!


15.  Does the Environmental Protection Agency (EPA) provide guidelines for school air and environmental guidelines?

Yes, both the EPA and the Illinois Emergency Management Agency, Department of Nuclear Safety (IEMA) provide Illinois Schools Environmental Guidelines to follow. 


An example of a School Environmental Health Program provided by the EPA which identifies five broad components that address school environmental health issues is outlined below:


  • Practice Effective Cleaning and Maintenance

  • Prevent Mold and Moisture

  • Reduce Chemical and Environmental Contaminant Hazards

  • Ensure Good Ventilation

  • Prevent Pests and Reduce Pesticide Exposure Voluntary Guidelines for States Development and Implementation of a School Environmental Health Program To learn more about this issue, see the EPAs Office of Children’s Health Protection 


16.  Will vacant or unoccupied buildings that have been closed for many days prior to the measurement return higher  results than occupied buildings?

No, most homes have an average air exchange rate of two hours (plus or minus one hour);  depending on the operation of the furnace and air movement within the building.  The twelve hour pre-measurement preparation allows for approximately four air-exchange cycles and allows for an accurate measurement of the radon concentration. 


17.  My builder says the home is radon resistant, that means I won't have elevated radon?

Even homes that have  integrated Radon Resistant New Construction (RRNC), the only way to know for certain that the RRNC is actually being effective is by performing a test.  

When explained further, Radon Resistant New Construction (RRNC),  is simply the installation of the radon system pipes without the fan.  Making the home "radon system ready," but certainly not resistant  to its entry.


*If buying from a builder, ask about the reimbursement options available on new RRNC homes that require the home have a fan installed on the home's radon system to make it meet standards.   Many builders offer free or discounted mitigation fan installation on new RRNC homes (if necessary).

18.  I don't live in an area with high radon, so am I safe here?

You won't know until you test for it.  Even the highest quality homes in areas that are determined to be low risk for radon can have high radon levels.  About 15% of homes in the U.S. have radon problems.

19. What is a high radon level?

There is no safe level of radon exposure.  Radon gas is measured in picocuries  per liter (pCi/L).  The current airborne radon level at which the EPA and IEMA recommend action is 4.0 pCi/L


[2]"A Physician's Guide | Radon | U.S. EPA." U.S. Environmental Protection Agency. (accessed December 24, 2014).

[3]"Health Risks | Radon | U.S. EPA." U.S. Environmental Protection Agency. (accessed December 24, 2014).

Credits:  NIR would like to thank the ACS, EPA, InterNACHI, NACHI and UIC for photos and graphs included in the website.