What Do Home Inspectors Need to Know About Radon?

June 4, 2021 | 
radon testing

While home inspections are mostly about identifying defects that are visible to the eye, inspectors sometimes test for the less-noticeable (but no less dangerous) problems that can afflict a house, such as lead paint, termites, and radon.

Radon gas buildup in the home can be deadly. It can happen to any house regardless of age or location, and it’s impossible to detect without specialized equipment. 

A good rule of thumb is to have every home inspected for radon when it’s put up for sale.

In this post, we’ll take a look at what radon is and the danger it poses to homeowners. Then, we’ll discuss the tools used for radon testing in a home inspection, and go over how you can become certified in radon measurement.

What is radon?

Radon is a radioactive gas that is emitted from decomposing uranium rocks, such as granite. It is a common element that is naturally present in the air in very small amounts, and it’s colorless, tasteless, and odorless.  

Because decomposing rocks are found everywhere, radon can be emitted from the ground and find its way up into a home through gaps in the foundation or basement walls. If a home relies on groundwater, radon can also be found in a home’s water supply.

Small traces of radon are normal; however, when radon is present at higher concentration, it increases the health risks to humans

In fact, radon exposure is believed to cause between 15,000 and 22,000 lung cancer deaths each year in the U.S. A concentration of 4 picocuries per liter (pCi/L) in the air poses the same risk of smoking half a pack of cigarettes per day.

That’s why Congress passed the Radon Program Development Act of 1987 to regulate the density of radon inside buildings to be the same as outdoors, and the Environmental Protection Agency produced the Home Buyer’s and Seller’s Guide to Radon to inform the public about health risks posed by this deadly gas.

Symptoms of radon poisoning

Unlike other hazardous gases like carbon monoxide, radon’s effects are not noticeable at first. Many homeowners don’t realize they’ve been breathing radon gas for years.

Unfortunately, there are currently no medical tests that you can use to check for unhealthy radon exposure, either. Many victims may feel completely fine for years, and then suddenly receive a diagnosis of lung cancer. 

Those who have been exposed to unhealthy levels of radon should be on the lookout for the following radon poisoning symptoms:

  • Wheezing and shortness of breath
  • Persistent cough
  • Hoarseness
  • Coughing up blood
  • Recurrent pulmonary infection like bronchitis or pneumonia
  • Chest pain, especially when coughing or laughing

If any of the above symptoms are present, contact your doctor right away. 

Is radon testing necessary for a home inspection?

Since there is no medical means to tell if you’re breathing in unhealthy levels of radon until you’ve developed a serious condition, homes should be tested for radon to ensure their air quality is not compromised.

There is no specific type or age of home that is more susceptible to unhealthy radon levels, either. Of course, there are a few characteristics of homes that can increase the risk of radon buildup, including:

  • Ground that is rich in thorium, uranium, or radium
  • A well-insulated home
  • A poorly ventilated ground floor or basement

The best time to test for radon is when a home is changing hands, which is why home inspections present the perfect time for radon testing. 

Do radon levels vary by state?

In the U.S., radon is measured in picocuries per liter (pCi/L), while Canadians measure radon in Becquerels per square meter (Bq/m3). On average, the outdoor concentration of radon falls between 0.135 and 0.405 pCi/L (or between 5 and 15 Bq/m3). In a home, anything above 2 pCiL is considered high.

High radon levels can occur anywhere; however, an area with higher radon levels may have a higher demand for radon testing—so if you’re considering adding radon testing to your list of services, it might be useful to know whether your area commonly sees high levels of radon.  

The EPA has created local and state-specific maps designed to show areas of high, medium, and low risk of radon concentration.

However, these maps shouldn’t be used as a guide for individual homes. Regardless of where a home is located, it’s best to get it tested for radon, since unhealthy radon gas levels can be found anywhere.

What tools do home inspectors use to test for radon?

When a home inspector conducts a radon test, the tools they use are usually either passive or active devices

Passive radon testing devices

A passive device can function without a power source. They are left at the testing site to absorb the particles in the air, and then they are sent to a lab for analysis. 

Passive devices are significantly more affordable than active testing devices, which appeals to some home inspectors. Passive devices include short-term and long-term testing kits.

Short-term testing: Charcoal canisters and liquid scintillation detectors 

These test kits are designed to gather data for two to four days before being returned to the laboratory for analysis. 

Both charcoal canisters and liquid scintillation detectors contain activated charcoal, which absorb radon and radon decay products. Lab analysis involves using either a sodium iodide detector or a liquid scintillation counter to measure the radon concentration in the air.

Charcoal canisters and liquid scintillation detectors should both give the same result, though the liquid scintillation tests are usually easier to use and are less expensive.

Long-term testing: Alpha track detectors

Alpha track detectors are designed for long-term use, usually 90 days up to a full year. These test kits work by absorbing the impact of alpha particles, which are released during the decay process of radon. Lab analysts count the tracks left in the device’s chip and use that number to calculate the concentration of radon in the air. 

Because alpha track detectors stay in the home for several weeks at minimum, their results tend to be the most accurate. However, this long-term test is usually not practical for home inspectors or their clients, who usually want the complete inspection report within a few days.

Active radon testing devices

Active devices need power (battery or electricity) to function, and they are often used by a trained tester. Although they are more expensive, they have many benefits that appeal to home inspectors, including instantaneous results. 

They also provide very detailed data on variance within the test period and whether the test was interfered with or tampered with. Active testing devices also should fulfill all state requirements for radon testing.

Continuous radon monitors (CRMs)

Continuous radon monitors use sensors to analyze collected air. The CRM’s electrical readout provides a report in real-time (often after the first 10 minutes of collection) and throughout the inspection process.

Continuous working level monitors

Continuous working level monitors are similar to CRMs. They draw air through a filter cartridge and use an alpha detector to count the particles produced by radon decay products over a certain time period (or several separate time periods). 

How can I add radon testing to my list of services?

If you’re interested in learning how to conduct a radon test—whether as a new home inspector or as a seasoned veteran—the first step is to take a radon measurement class that’s approved by the National Radon Safety Board (NRSB).

Then, pass the NRSB’s certification exam—or pass another exam administered through an approved training program, such as:

  • The International Association of Certified Indoor Air Consultants (IAC2), which is created by and affiliated with the International Association of Home Inspectors (InterNACHI)
  • The Residential Radon Measurement course offered by the American Society of Home Inspectors (ASHI) school
  • Radon Testing Corporation of America (RTCA) courses
  • The National Radon Proficiency Program (NRPP) certification course offered by the American Association of Radon Scientists and Technologists (AARST)

As part of the application process, inspectors will need to specify and register the device they plan to use. If you plan to use a continuous radon monitor (CRM) or continuous working level monitor, you’ll need to take a proficiency test and pass a calibration certification test to make sure you can keep the devices in good working order.

Finally, you’ll need to take 16 hours of continuing education annually and pay the membership dues to remain a member of the NRSB in good standing. A radon measurement professional may go on to become a radon mitigation specialist, which involves designing and installing systems to help lower the radon levels in a home.

Final thoughts

As a home inspector, you likely take pride in being as thorough as possible for your clients. After all, their new home should be a safe place, and your inspection report should deliver as much information as possible to help your clients make the right decision for their family. 

Radon is nearly impossible to detect without specialized equipment, but it can cause devastating health effects. Any new homeowner should make sure to have their property tested for radon—and you may want to consider adding radon testing to your list of services.

For more information about promoting your radon testing service, check out the HomeGauge Learning Center. We’re here to help you build your inspection business, add services, and give you the right tools for long-term success.