Health

Radon

Radon is a naturally occurring, colorless, and odorless radioactive gas that comes from the soil and enters homes and other buildings through small openings like cracks in foundations, openings around pipes, pumps, drains, and crawl spaces. The U.S. Environmental Protection Agency  recommends taking action to fix your home when radon levels are equal to or above 4 picocuries per liter (pCi/L).

Radon Risk

We are exposed to background radiation throughout our lives, with radon being the largest source of background radiation in the United States. Prolonged exposure to elevated levels of radon inside a home can pose a serious health threat. Radon is the leading cause of lung cancer among nonsmokers and contributes to up to 500 cancer deaths annually in Colorado.

Radon risk is often compared to chest X-rays to help people picture the danger in their homes. Unlike a one-time X-ray which passes through the body, radon is breathed in every day and the radiation builds up in the lungs damaging cells. These damaged lung cells become cancerous over time. Living in a home with a radon level of 4 pCi/L for one year exposes your lungs to about the same radiation as 200 chest X-rays over a year. 

Any home may have high levels of radon, even if neighboring homes do not. The only way to know if your home has harmful levels of radon is to test.

Test Your Home

Mitigate Your Home

Many people choose to hire a contractor to mitigate their home for radon. The Colorado Department of Regulatory Agencies (DORA) certifies and maintains a list of radon mitigation professionals.

If you need financial assistance to help you mitigate your home, the Colorado Department of Health and Environment has a Low Income Radon Mitigation Assistance Program for qualifying homeowners.  In Larimer County, a four-person household making equal to or less than $102,100 would be eligible for financial assistance.

Radon in Colorado

Radon in Colorado PSA

 El radón en Colorado

Map of Radon Testing Results in Larimer County

The map above shows radon test results in Larimer County. Results below the EPA's recommended action level are shown in blue. The average radon level in the area is 7.8 pCi/L (picocuries per liter), which is higher than the national average of 1.3 pCi/L. The highest level of radon tested in Larimer County was 1,147 pCi/L. The EPA advises that homes with radon levels of 4 pCi/L or more should have mitigation systems installed.

FAQs

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  1. What is radon?

    Radon is a naturally occurring radioactive gas that is formed when radioactive metals break down in rocks, soil, and groundwater. You cannot see, smell, or taste radon.

    Radon can seep into your home through the ground. Over 50% of homes in Colorado have elevated levels of radon.

    The U.S. Environmental Protection Agency recommends radon be mitigated if the level is 4 picocuries per liter (pCi/L) or more. The only way to know if your home has harmful levels of radon is to test for it. If your home tests above the EPA action level, you are at an elevated risk of developing lung cancer from radon.

    Health Effects of Radon

    Radon is the leading cause of lung cancer in non-smokers. It is the second leading cause of lung cancer overall. Each year, radon is responsible for about 21,000 lung cancer deaths in the United States, with about 2,900 of these deaths occurring in people who have never smoked.

    Smokers have a higher risk of developing lung cancer from radon exposure. However, there is no evidence that radon causes other respiratory diseases like asthma, and there is no evidence that children are at a higher risk of lung cancer from radon than adults.

    More information: CDPHE Radon Information

  2. How do I test for radon?

    Test for radon with a “do it yourself” radon test kit. Home test kits are easy to use and affordable. 

    • The test kit is placed in your home and exposed to to sample the indoor air after closing all openings (windows, doors, etc).
      • The best time to test for radon is during the winter months when doors and windows are closed to reduce ventilation and trap heat, allowing radon concentrations to peak.
    • The test kit will need to be activated (or opened) and remain in place for a specific period of time - from a few days to several weeks.
    • Each kit will come with its own specific instructions for testing and shipping. Please follow the test kit instructions carefully. 

    Please refer to the list above for radon test kit resources under Test Your Home.

    Instead of a do-it-yourself test kit, you can also hire a licensed radon measurement professional. Please note if testing radon for a real estate transaction, a licensed radon measurement professional shall conduct the short term radon measurement using a professional-grade Continuous Radon Monitor or other approved test device.

    Colorado residents can get a free radon test kit, funded by the Colorado Department of Public Health and Environment. The kits are mailed from Alpha Energy Labs. Use this link to order one: Free Test Kits for Colorado Residents

    You can also purchase a radon test kit online and in many retail or hardware stores.

  3. What is radon mitigation?

    Radon mitigation involves taking steps to reduce the level of radon in your home. Installing radon mitigation systems is the best way to reduce elevated radon levels. The most common and effective system is a sub-slab or sub-membrane depressurization system that pulls radon gas from the soil below your foundation and redirects the gas to the outdoors via a pipe, reducing radon from entering the home. The Colorado Department of Health and Environment estimates for most homes, this will cost about $1,000 - $,3000.

    When should I mitigate for radon?

    If your home tests at 4 picocuries per liter (pCi/L) or more, the EPA recommends you mitigate your home for radon. Because there is no known safe level of exposure to radon, EPA also recommends that Americans consider fixing their home for radon levels between 2 pCi/L and 4 pCi/L.

    Can I mitigate for radon myself?

    To temporarily lower radon levels before a radon mitigation system is installed, homeowners should increase ventilation in their home by opening windows and using fans. Sealing cracks and openings in floors, walls and around pipes. can also assist in reducing points of entry for the radon gas but are not enough to improve indoor air quality.

    It is strongly recommended that homeowners hire a licensed radon mitigation professional to properly reduce radon levels in their home. 

    If choosing to mitigate your own radon levels, it is important to check with your local building department on required permits before making any modifications to your home’s foundation or electrical. Note that a do-it-yourself radon mitigation system may not meet local building codes and may need to be replaced before selling the home.

    The Colorado Department of Public Health and Environment provides educational resources for do-it-yourself radon mitigation information under the “Mitigating your home for radon” dropdown menu.

    Where can I find a contractor?

    It is strongly recommended that homeowners hire a licensed contractor to mitigate their home for radon. The Colorado Department of Regulatory Agencies (DORA) certifies radon mitigation professionals.  Check to see if your selected contractor is licensed by DORA.

  4. What if I need financial assistance for radon mitigation?

    The Colorado Department of Public Health and Environment offers financial help to reduce radon in homes through the Low Income Radon Mitigation Assistance program. If you meet certain income requirements, the program can cover up to 100% of the cost to install a radon mitigation system in your home by a certified professional. For more details about this financial assistance, visit their website.

    Some Health Savings Accounts (HSA) or Flexible Spending Accounts (FSA) may pay for a radon mitigation system. Check with your plan to see if you qualify.

  5. My neighbor tested for radon. Do I need to test too?

    Yes. Your home’s radon level can be very different from your neighbor’s. The soil under your homes may be similar, but your home’s structure and foundation are unique.

    For example, if your home has a crawl space and your neighbor’s house does not have a crawl space, this can impact the radon reading. Additionally, the cracks and holes in you home's foundation will be different from your neighbor's home.  

    The only way to know if your home has a radon problem is to test for it.

  6. How often should I re-test my home?

    The EPA recommends re-testing radon levels every two years to verify the radon mitigation system is operating effectively. It is also recommended to test for radon in the following scenarios: 

    • If your test results are 4 pCi/L or more, it is recommended to take a follow-up test to confirm.
    • If your first short-term test result is more than twice the Environmental Protection Agency’s 4 pCi/L action level, it is recommended that you take a second short-term test immediately.
    • Before and after any home renovations;
    • Re-test after your neighbor expands their home foundation due to the change in soil;
    • If your living patterns change (ex: start occupying the basement more often as a bedroom, office, family room);
    • If you purchased a home that does not have a radon mitigation system but the radon test result was less than 4 piC/L;
    • If you purchased a home during the warmer months when houses are not as sealed up, retest your home in the winter months.
  7. What if I'm renting my home?

    As of August 7, 2023, Colorado landlords must disclose radon information when a tenant signs a lease agreement. Tenants can void their lease if the landlord does not include the radon disclosure or if a landlord does not make reasonable efforts to mitigate elevated radon levels after 180 days.

    A Radon Guide for Tenants - from the Environmental Law Institute (ELI) and the U.S. Environmental Protection Agency

  8. Should I test my mobile home for radon?

    Any building that touches the ground is at risk of radon exposure. The type of foundation a mobile home has is the main factor in deciding whether testing should be done. 

    • Mobile homes with a concrete or block wall foundation have the highest risk.
    • Mobile homes on piers, blocks, or axles with skirting are at moderate risk.
    • Mobile homes without skirting have the lowest risk. Radon moves through the ground and will travel the easiest path, so if it can escape from under the mobile home, the risk is lower. However, if there are walls or skirting blocking its escape, it may rise into the living space. 

    The Health Department recommends that everyone test their home for radon.

  9. Radon information for childcares

    Radon test reports must be kept at the child care facility and be available for anyone who asks to see them.

    Test Results

    Radon measurements show how much radon was present during the test. Radon is measured in picocuries per liter (pCi/L), a unit of radioactivity. The EPA recommends taking action if radon levels reach 4 pCi/L.

    If the test results are below 4 pCi/L, no action is needed, but it's good to test every 5 years to keep track of the levels.

    If a room shows levels between 4 pCi/L and 8 pCi/L, it's recommended to do a longer test in that room. If the long-term test shows levels above 4 pCi/L, you should consider mitigating the radon.

    If a room shows a result higher than 8 pCi/L, do another short-term test in that room. If the levels are still above 8 pCi/L after the second test, radon mitigation is recommended.

    Mitigation

    While Colorado's child care regulations don't require radon mitigation, it is strongly recommended when radon levels are 4 pCi/L or higher. The cost of mitigation depends on how the facility was built and the severity of the radon problem. There are several ways to reduce radon levels.

    For rooms with radon levels between 4 pCi/L and 8 pCi/L, sometimes small changes to the heating, ventilation, and air conditioning (HVAC) system can help by increasing airflow to those rooms.

    More complex mitigation systems can also be used, such as sub-slab depressurization or suction systems that remove radon gas and release it safely into the air. These systems should only be installed by a certified contractor. The Colorado Department of Public Health & Environment has a list of certified contractors who can perform radon mitigation. See Testing and mitigating your home for radon.

    After radon mitigation work is finished, re-testing should always be done to make sure the radon levels have been reduced to below 4 pCi/L.