Real Talk about Radon in Flagstaff: An Interview with Bill Branch at 121 PRO Home Inspections

radon equipment with arizon inspector bill branch

Clear Sky Professionals Team Lead, David Swain, speaks to Bill Branch, owner of 121 PRO Home Inspections about Radon. The above pictured radon testing units include examples from AlphaGUARD, E-Perm®, and Femto-Tech LPTs.

Bill, why is it important for homeowners to be educated about radon?

Radon is a naturally occurring gas that can make its way through a home’s foundation and, at high levels and over prolonged exposure, can lead to lung cancer. In Northern Arizona, we have higher levels of radon than many other parts of the country because we have a lot of limestone (Flagstaff, Parks, & Williams), granite (Prescott & surrounding areas) and aquafers. These regions are more likely to give off higher levels of radon as these types of natural formations decompose.

How does Radon enter the home?

Radon can enter the home through porous foundations, cracks, unsealed vents, and improperly installed HVAC systems. Additionally, radon may enter the house when the interior pressure of the house is less than the exterior pressure. To oversimplify, the house acts as a vacuum. This is a common occurrence when the exterior temperatures are lower than the interior temperature of the house. As a result, this creates an upward movement of air, commonly referred to as the 'stack effect.’

How does someone reduce radon concentration in the home?

Preferably, professional radon mitigators can install depressurization systems under the foundation of a house to reduce the risk of radon entry as well as other earth gasses. Alternatively, air-exchangers, which connect to the HVAC systems, can dilute the radon levels.

What are some common myths that people have about radon gas?

Myth: Radon is poisonous gas.

Bill explains that radon is not poison, nor is it harmful on its own, however the natural breakdown of radon atoms inside the lungs can damage the mitochondrial DNA within an epithelial lung cell, the damaged DNA is the culprit that causes lung cancer. Long exposures to higher levels of radon increase the lung cancer risk. 

Myth: If your neighbor’s house tests high for radon, that means my house will test high as well.

Bill explains that even in areas where most homes will test above the EPA’s Recommended Action Level for Radon (like Parks, AZ), a home in that area can have lower levels of radon because the geology under the house is different than the surrounding houses. For example: The rock is decomposing at a different rate, there are less cracks in the rock or less water (aquifers or underground streams).

Myth: All Radon testing devices are reliable.

Bill explains that professional level radon measurement devices are necessary for real estate transactions, due to their level of high precision, when testing for shorter periods of time such as 48 to 60 hours. Bill further explains that Consumer Grade radon measurement devices are intended to monitor home environments for 30+ or more days; The greater number of monitoring days increases the accuracy of the results. They are less reliable for short term testing such as real estate transaction. 

When working with a certified radon professional, they will use high precision radon detection monitors approved by the National Radon Proficiency Program (NRPP). The certified radon professional is trained to properly place the device in the house for the most optimal & accurate reading of the home. Ideally, the radon professional should be able to clearly communicate to the homeowner how to read the results and what the results mean.

What is the typical cost for radon mitigation services?

Radon remediation systems improve indoor air quality and, in turn, reduces levels of radon. While costs can vary depending on the type of system that needs to be installed, most typically range from $2000 for simple systems and up to $5000 for more complicated systems.

What’s the best piece of advice you’ve ever been given?

Someone once mentioned over a casual conversation that I should apply Game Theory to everything that I do.

Since your company is currently hiring, what qualities or skills do you look for in potential team members?

I need a professional that is attentive to details and customer service with an unbridled desire to ask questions, learn, and grow. A quote that I live by: "A relentless barrage of 'why's' is the best way to prepare your mind to pierce the clouded veil of thinking caused by the status quo. Use it often" -Shigeo Shingo

If 121 PRO Home Inspections had a soundtrack, what three songs would be on it?

Van Halen - Right Now
Stix - Mr. Roboto
Oingo Boingo - Dead Man’s Party

Bill Branch is a Certified Master Inspector in Flagstaff and Sedona with testing certifications in Radon, Mold, Asbestos, and Lead. Bill has taken over 900 hours of continuing education in his field beyond anything that is required.

Bill is the proud father of 3 Daughters and 2 Huskies, and volunteers in his free time to help elderly folks.

To get in touch with Bill, you can email him directly at [email protected] or visit: 

For more information on Radon, visit or download a Home Buyer’s and Seller’s Guide to Radon.

For radon remediation contact [email protected], or visit

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