A radon mitigation system is built to pull radon from beneath your home and vent it outside. But a fan and a vent pipe do not tell you what the air indoors actually looks like. EPA recommends retesting after a system is installed, and that is what post-mitigation testing is.
If you live in Prescott or nearby and want a follow-up test, call (928) 582-8914. You will be connected with licensed and insured local radon professionals who can test the home and talk through the result.
Why retest after a system goes in
Radon has no color, smell or taste. You cannot see or feel a system working, and testing is the only way to know a home's radon level. A retest compares your new result with the number that led to the system in the first place.
EPA recommends fixing a home when the level is 4 pCi/L or higher, and says homeowners should consider fixing it between 2 and 4 pCi/L. The follow-up test shows where your home now stands against those numbers.
This matters in Prescott. The Granite Dells granite just north of the city has an unusually high uranium content, and the Arizona Geological Survey notes that radon from this granite is a concern for people who build weather-tight homes on it. A tight, energy-efficient house can hold radon in, so confirming the result is worth doing.
How a post-mitigation test is done
The same kinds of tests used before mitigation are used afterward. A short-term test stays in place from 2 to 90 days. A long-term test stays more than 90 days and better reflects the year-round average.
Short-term tests are done under closed-house conditions. Windows and outside doors stay closed except for normal coming and going. The device goes in the lowest lived-in level of the home.
Prescott has day-to-night temperature swings that average nearly 30 degrees F. It is easy to crack a window on a mild afternoon, but that can change the reading. Keeping the house closed during the test makes the result easier to trust.
Reading the system's pressure gauge
Many systems have a simple pressure gauge on the vent pipe. It shows that the fan is running. Checking it now and then is a quick way to notice a problem.
The gauge does not measure radon. It only shows that the system is operating. A normal-looking gauge is not a substitute for a test, and a test is not a substitute for checking the gauge. If the gauge looks different than it did after installation, or you think the fan has stopped, call and ask a local professional to take a look.
When to test again
EPA recommends retesting every two years or so after a system is installed. A regular schedule helps you catch a change early. Mark the date on a calendar or tie it to something you already do each year.
Also retest after major renovations. New walls, a finished basement, added rooms, new flooring over a slab or work on the foundation can change how air moves through a home. A change in how the home is used can matter too, such as turning a storage area or a lower level into living space. The lowest lived-in level is where tests are placed, so that level should be tested again.
A test result from before the system was installed, or from a previous owner, may not reflect the home today. Renovations are one reason why.
Homes with crawl spaces, wells or older construction
Prescott has a mix of housing, from Victorian homes near downtown to newer subdivisions toward the Granite Dells, Prescott Lakes and Willow Creek Road. Foundation type and layout vary a lot. That affects how a system is designed, but it does not change the need to confirm the result with a test.
Homes with private wells can have an additional pathway. Gaps in a well casing can let radon in, and radon in well water can be released into the air when water is used. Well water is tested separately from air. For most homes, radon in air is the larger concern.
Help across the Prescott area
Help is available in Prescott, including neighborhoods such as Yavapai Hills, Miller Valley, Forbing Park, Fort Whipple and Diamond Valley. It also covers nearby Prescott Valley, Chino Valley and Dewey-Humboldt, and the rest of Yavapai County.
Arizona does not run a state radon certification program. EPA recommends hiring a nationally certified radon professional, certified through the National Radon Proficiency Program or the National Radon Safety Board. When you call (928) 582-8914, you are connected with licensed and insured local professionals. Cost depends on the home's foundation type, size and layout, so a professional gives a quote after looking at the home.
What to do next
If a system was recently installed and you have not retested, that is the first step. If it has been about two years, or you have remodeled, it is time to test again. Either way, a quick call to (928) 582-8914 is a simple way to get started.