Radon in Union County, Pennsylvania

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

2,791 home tests, 2016–2026, Pennsylvania DEP
  • Below 2 pCi/L: 37%
  • 2 to 4 pCi/L: 25%
  • 4 pCi/L or more: 38%
The line marks the EPA action level, 4 pCi/L.
Typical level
3.0 pCi/L
EPA radon zone
Zone 1
In Pennsylvania
39th 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 Union County

From 98 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 Union 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
Mifflin County67%
Centre County67%
Snyder County65%
Union County63%
Northumberland County60%
Clinton County56%
Lycoming County53%
Pennsylvania41%
United States36%

Radon by zip code in Union County

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

Zip codeHomes testedTests4 or moreMedian
17837
1,76135%2.8 pCi/L
17844
48248%3.8 pCi/L
17889
20341%3.3 pCi/L
17856
15045%3.3 pCi/L
17855
6045%3.8 pCi/L
17886
4831%2.3 pCi/L
17845
4142%3.3 pCi/L
17810
3949%3.8 pCi/L
17835Too few tests2––
17885Too few tests2––
17887Too few tests2––
17829Too few tests1––

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

Sources

Last updated October 2026. How we calculate these numbers.