Radon Testing & Mitigation in Sullivan County, PA
40% of 614 basement radon tests reported to PA DEP in Sullivan County measured 4.0 pCi/L or higher, EPA's action level (median 3.1 pCi/L).
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Radon in Sullivan County: 40% of the 614 basement tests reported to PA DEP measured 4.0 pCi/L or higher, EPA's action level, 3 points above the 37% statewide share. The county ranks 48th highest of 67, and the median result is 3.1 pCi/L. Only a test shows one home's level.
Radon Test Results by ZIP Code in Sullivan County
6 ZIP codes in Sullivan County have at least 20 basement tests on record. Among those with 100 or more, the highest share at or above 4.0 pCi/L is in 18614 (Dushore): 43% of 169 tests. The lowest is in 18626 (Laporte): 37% of 103 tests.
| ZIP code | Post office | Basement tests | Median pCi/L | At or above 4.0 |
|---|---|---|---|---|
| 18614 | Dushore | 169 | 3.3 | 43% |
| 17731 | Eagles Mere | 155 | 2.9 | 39% |
| 18626 | Laporte | 103 | 3.1 | 37% |
| 17758 | Muncy Valley | 71 | 3.4 | 44% |
| 18616 | Forksville | 60 | 2.4 | 33% |
| 17768 | Shunk | 20 | 3.5 | 35% |
| Sullivan County | 614 | 3.1 | 40% | |
| Pennsylvania | 2,629,492 | 2.8 | 37% | |
See your ZIP in the table?
Get matched with a DEP-certified radon professionalFirst-floor tests in Sullivan County: 173 on record, median 1.2 pCi/L, 16% at or above 4.0 pCi/L.
EPA's Map of Radon Zones (1993) places Sullivan County in Zone 1, its highest category (predicted average indoor screening level above 4 pCi/L). The map is a county-wide prediction; the figures in this table are measurements.
Figures count tests, not homes. A home tested more than once is counted each time, and tests run after a mitigation system was installed are included because the dataset does not separate them. ZIP codes with fewer than 20 basement tests are not shown.
Housing Age in Sullivan County
61% of Sullivan County's 5,584 housing units were built before 1980, 6 points below the 67% statewide figure; 27% date from before 1940. Those homes predate EPA's 1994 model standards for radon-resistant construction. Age does not predict a test result: EPA's guidance is that any home, new or old, may have a radon problem.
Source: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, table B25034. Counts all housing units, including vacant and seasonal ones. Retrieved September 29, 2026.
Bedrock Under Sullivan County
Catskill Formation (Devonian; sandstone, shale and siltstone) underlies 32% of the county. Huntley Mountain Formation (Mississippian and Devonian; siltstone and sandstone) underlies 30% of the county.
Mapped bedrock describes an area. The USGS states that its radon assessment cannot be applied to individual homes. More on Pennsylvania radon and geology.
Sources: U.S. Geological Survey State Geologic Map Compilation, from Pennsylvania Geological Survey Map 1 (1980; digital edition 2001). Retrieved September 29, 2026. U.S. Geological Survey Open-File Report 93-292-C, Geologic Radon Potential of EPA Region 3 (1993).
Private Wells in Sullivan County
An estimated 79% of Sullivan County residents supplied their own household water in 2015, typically from a private well. Radon dissolves in groundwater and is released into indoor air when water is used for showering and other household purposes. EPA's guidance: if an air test finds a radon problem and your water comes from a well, have the water tested too. A water test is separate from an air test.
Sources: U.S. Geological Survey, Estimated Use of Water in the United States, county-level data for 2015. Retrieved September 29, 2026. U.S. EPA, A Citizen's Guide to Radon.
Home Purchases in Sullivan County
Lenders reported 78 home-purchase mortgages originated in Sullivan County in 2024. The count covers financed purchases only; cash purchases are not in the data. See radon in a Pennsylvania home sale.
Source: FFIEC Home Mortgage Disclosure Act data, 2024. Retrieved September 29, 2026.
Municipalities in Sullivan County
Sullivan County has 13 municipalities: 4 boroughs and 9 townships.
Show all 13 municipalities
Cherry township, Colley township, Davidson township, Dushore borough, Eagles Mere borough, Elkland township, Forks township, Forksville borough, Fox township, Hillsgrove township, Laporte borough, Laporte township, Shrewsbury township.
Source: U.S. Census Bureau, 2025 Gazetteer Files, county subdivisions. Retrieved September 29, 2026.
City Pages in Sullivan County
Neighboring Counties
- Radon in Bradford County → 49% of 4,688 basement tests at or above 4.0 pCi/L
- Radon in Columbia County → 51% of 10,235 basement tests at or above 4.0 pCi/L
- Radon in Luzerne County → 31% of 54,988 basement tests at or above 4.0 pCi/L
- Radon in Lycoming County → 46% of 15,366 basement tests at or above 4.0 pCi/L
- Radon in Wyoming County → 43% of 4,060 basement tests at or above 4.0 pCi/L
- All 67 Pennsylvania county radon pages
DEP-Certified Mitigation Firms Based in County
No DEP-certified mitigation firms are physically based in Sullivan County. Certified professionals from adjacent counties travel here to perform testing and mitigation.
Source: PA DEP Certified Mitigation Firms Directory, July 2026. This reflects business address only — firms based elsewhere may also serve Sullivan County.
Testing, Cost and Certification
Short-term tests run 48–96 hours; long-term tests run 90 days or more. At 4.0 pCi/L or higher, retest or mitigate. How radon testing works in a Pennsylvania real estate transaction.
Mitigation in Sullivan County typically costs $950–$2,100. Pennsylvania radon mitigation cost guide.
Anyone testing or mitigating for pay must hold DEP certification under 25 Pa. Code § 240. How to verify a contractor in the PA DEP Radon Services Directory.
Frequently Asked Questions
What share of radon tests in Sullivan County are at or above the EPA action level?
40% of the 614 basement tests reported to PA DEP from Sullivan County measured 4.0 pCi/L or higher, against 37% statewide. The median result is 3.1 pCi/L, and 4% of tests measured 20 pCi/L or higher.
Which Sullivan County ZIP code has the highest radon test results?
Among ZIP codes with at least 100 basement tests, 18614 (Dushore) has the highest share at or above 4.0 pCi/L: 43% of 169 tests, with a median of 3.3 pCi/L. 18626 (Laporte) has the lowest, at 37%.
How does Sullivan County compare with other Pennsylvania counties?
Sullivan County ranks 48th highest of 67 counties by share of basement tests at or above 4.0 pCi/L, at 40%. Among its neighbors, Columbia County has the highest share at 51% and Luzerne County the lowest at 31%.
What bedrock is under Sullivan County?
The largest mapped units are Catskill Formation (32% of the county) and Huntley Mountain Formation (30% of the county), according to the USGS compilation of the Pennsylvania Geological Survey state map.
Should Sullivan County well owners test their water for radon?
An estimated 79% of Sullivan County residents supplied their own household water in 2015. EPA's guidance is to test the air first. If the air test finds a radon problem and the water comes from a well, have the water tested as well.