Radon Testing in Clovis

Clovis sits in the heart of the San Joaquin Valley, where the underlying geology, granite-derived soils and decomposed granite alluvium washing down from the Sierra Nevada foothills, creates conditions that can elevate radon concentrations in homes across the area. Radon is a colorless, odorless gas that forms naturally as uranium in soil and rock breaks down, and in a city where single-family homes often sit on slab or raised foundations over this mineral-rich ground, the gas can accumulate indoors without any visible warning sign. If you’re buying, selling, or simply want to know what your family is breathing, a professional radon test is the place to start.

Why Clovis Properties Can Have Elevated Radon Levels

The Sierra Nevada foothills that frame Clovis to the east are composed largely of granite and granitic soils, rock types that tend to carry higher concentrations of naturally occurring uranium. As those soils weather and migrate into the valley floor, they bring radon-producing material with them. Homes built on the eastern edges of Clovis, closer to the alluvial fan deposits that spread out from the foothills, may face a different risk profile than properties closer to the valley center.

Clovis also has a wide range of housing stock. Newer master-planned subdivisions built with tight energy-efficient envelopes can trap radon more effectively than older, draftier construction, because the same insulation and sealing that keeps summer heat out also keeps soil gases in. Conversely, older homes with crawl spaces or unsealed slab penetrations offer more pathways for radon to enter. Neither age nor construction style is a reliable predictor on its own; testing is the only way to know.

California does not currently mandate radon testing at the point of sale the way some states do, but that doesn’t mean the risk doesn’t exist. The EPA designates much of California’s Central Valley as a region warranting radon awareness, and Fresno County, which includes Clovis, falls within that broader zone of concern.

Our Radon Testing Process in Clovis

Arch Environmental Group uses continuous electronic radon monitors rather than passive charcoal canisters for most residential tests. Continuous monitors log radon concentrations hour by hour over the test period, which gives a more complete picture of how levels fluctuate with changes in weather, HVAC operation, and daily activity patterns, all of which matter in a climate like Clovis’s, where hot summers and mild winters mean residents shift between open-window ventilation and sealed, air-conditioned interiors throughout the year.

The testing process follows EPA and state protocols: monitors are placed in the lowest livable area of the home, typically a ground-floor room or finished basement if present, and left undisturbed for the required closed-house period. At the end of the test, the monitor data is downloaded and analyzed. Results are provided in picocuries per liter (pCi/L), with the EPA action level set at 4 pCi/L. If levels come back at or above that threshold, the report will outline what mitigation options typically look like, though mitigation itself is a separate scope of work.

Because Arch Environmental Group holds certifications in environmental consulting and industrial hygiene disciplines, the testing is conducted with the same documentation rigor used for commercial and real-estate transaction work, not a drop-and-forget kit.

Reaching Clovis from Kingsburg

Arch Environmental Group is based in Kingsburg, roughly 25 miles south of Clovis via Highway 99 and then east on Shaw Avenue or Herndon Avenue depending on the specific address. Scheduling is handled by phone at (559) 296-2088. Because radon testing requires a closed-house period and advance coordination, same-day testing is rarely appropriate, contact us to arrange a test window that fits your timeline, whether that’s tied to a real estate contingency deadline or simply your family’s schedule.

Local Note

One thing worth knowing about Clovis specifically: the city has grown rapidly through annexation of unincorporated Fresno County land, which means some neighborhoods that carry a Clovis mailing address were built under county, not city, building codes and inspection regimes. Homes in those transitional areas sometimes have foundation and sub-slab details that differ from what a Clovis city permit would have required, and those differences can affect how readily radon enters the structure. If your home was built on what was recently unincorporated land, it’s worth mentioning that when you call, it can inform where monitors are placed and how results are interpreted.

If you’ve been putting off a radon test for your Clovis home, the process is straightforward and non-disruptive. Call Arch Environmental Group at (559) 296-2088 to schedule a continuous radon monitoring test and get a clear, documented answer about what’s in the air your household is breathing every day.