Radon in Clarion County, Pennsylvania

About 4 in 10 homes tested here were at or above the EPA action level.

1,260 home tests, 2016–2026, Pennsylvania DEP
  • Below 2 pCi/L: 28%
  • 2 to 4 pCi/L: 29%
  • 4 pCi/L or more: 43%
The line marks the EPA action level, 4 pCi/L.
Typical level
3.5 pCi/L
EPA radon zone
Zone 1
In Pennsylvania
17th of 67

EPA Zone 1, the highest radon potential (predicted average above 4 pCi/L). The EPA zone map dates from 1993 and is meant for planning; high levels are found in every zone.

What fixing radon costs in Clarion County

From 50 standard systems installed in the county since 2021, as reported to the state. Half of homeowners paid between the low and high figures.

What to do next

  1. Test your home

    Radon levels vary between neighboring houses, so area data can't tell you your own home's level. A short-term test takes 2 to 7 days in the lowest lived-in floor. A long-term test (90 days or more) gives a more reliable average.

  2. If your result is 4 pCi/L or more, fix it

    A certified professional installs a sub-slab system: a pipe and a quiet fan that pull radon from under the foundation and vent it above the roof. It usually takes a day; the costs are above.

    It works: across Pennsylvania, the typical level dropped from 7.7 to 1.0 pCi/L after mitigation, and 95% of homes ended up below the action level.

  3. Use a certified professional

    Pennsylvania requires radon testers and mitigators to be certified. The state publishes the list of certified mitigation firms by county.

How Clarion County compares

Share of homes tested at or above 4 pCi/L, with neighboring counties. Lab data 2008–2017, the only source that covers every state.

Share of homes tested at or above 4 pCi/L
Jefferson County58%
Armstrong County58%
Butler County49%
Venango County48%
Clarion County48%
Forest County45%
Pennsylvania41%
United States36%

Radon by zip code in Clarion County

Home tests reported to the Pennsylvania DEP since October 2016, most-tested zip codes first.

Zip codeHomes testedTests4 or moreMedian
16214
42836%3.3 pCi/L
16254
13445%3.3 pCi/L
16049
10453%4.3 pCi/L
16232
10157%4.8 pCi/L
16242
8847%3.3 pCi/L
16028
8043%3.3 pCi/L
16258
5052%4.3 pCi/L
16235
4947%3.8 pCi/L
16224
4856%4.3 pCi/L
16233
4536%2.3 pCi/L
16255
3928%2.8 pCi/L
16248
3653%4.3 pCi/L
16326Too few tests12––
16334Too few tests11––
16220Too few tests9––
16054Too few tests8––
16225Too few tests5––
16260Too few tests4––
16036Too few tests2––
16230Too few tests2––
16332Too few tests2––
16213Too few tests1––
16331Too few tests1––
16361Too few tests1––

"–" means fewer than 20 tests, too few for a reliable figure.

Sources

Last updated October 2026. How we calculate these numbers.