Township, York County

Radon Mitigation in Hellam Township, PA

Updated September 30, 2026

Hellam Township runs along the Susquehanna River east of York, next to Wrightsville. It is mostly detached homes, 90% owner-occupied, and one home in ten is a mobile home. Most of it is in ZIP 17406, with the Wrightsville side in 17368. 17368 has a median of 5.2 pCi/L, and its highest recorded reading is over 1,000 pCi/L, one of the highest single tests in the county.

What the PA DEP test records show for Hellam Township

ZIP codes don't follow township lines, so the 2 ZIP codes below also take in some homes just outside Hellam Township.

• ZIP 17406 (about 75% of Hellam Township's land): median 4.3 pCi/L across 4,025 tests, 14.3% at 20 or higher, top reading 410. Basement median 5.3, first floor 1.7.
• ZIP 17368 (about 18% of Hellam Township's land): median 5.2 pCi/L across 1,351 tests, 16.3% at 20 or higher, top reading 1,041. Basement median 7.5, first floor 2.9.

The spread inside Hellam Township runs from 52.6% of tests high in 17406 to 56.9% in 17368.

The share that matters most is the 20+ column. 14.8% of tests here came in at 20 pCi/L or more, five times the action level. The single highest reading on record in these ZIP codes is 1,041 pCi/L. Neighboring houses can differ by a factor of ten, so none of this tells you what your house is. It tells you the odds are high enough that a $15 to $30 test kit is worth buying.

Tests people chose to run, not a random survey. Details on the York County radon levels page.

Basement readings versus first-floor readings

In ZIP 17406, basement tests have a median of 5.3 pCi/L, while tests taken on the first floor have a median of 1.7 pCi/L (610 first-floor tests). The basement number runs 3.1 times the first-floor number, which is the usual pattern: radon comes up from the soil, so it is strongest at the lowest level and gets diluted as it moves up through the house.

It also explains why two neighbors can get very different results. One tested a finished basement, the other tested a first-floor bedroom. For a decision about mitigation, the test that counts is the one from the lowest level anyone spends time in.

Radon results by decade in ZIP 17406

The share peaked in the 2000s at 64.9% and sits at 45.1% for tests since 2020. A drop that size is mostly about who is testing, not the ground. More recent tests come from home sales and from retests after a system went in, and both pull the share down. The rock under Hellam Township has not changed. 993 tests have been logged in 17406 since 2020, so people here are still testing.

The ground under Hellam Township

Hellam is in the Piedmont Upland, and it has some of the best-documented rock in the state. The Peters Creek Schist, overlain by Chickies quartzite, is exposed in the classic Wrightsville section inside the township (USGS Geolex).

That matters for radon. In a USGS study of 16 Pennsylvania rock units, the Peters Creek Schist had the highest median groundwater radon of all of them, and USGS flagged it as the area with the highest potential radon exposure from both groundwater and indoor air.

Housing in Hellam Township and what it means for a system

Census Bureau, American Community Survey 2020 to 2024:

10% of homes in Hellam Township are mobile or manufactured homes, well above the county's 4.1%. Those sit over a crawlspace or skirted pad rather than a basement, and the fix is different: a sealed membrane over the soil with suction under it. See crawlspace radon for what that involves.

80.5% of homes in Hellam Township are single-family detached. A detached house with a basement is the easiest layout to mitigate: one suction point through the slab, a fan outside or in the garage, and a vent above the roof line. It is the standard sub-slab depressurization job covered step by step on our mitigation process page, and it usually lands in the middle of the cost range.

Cost-wise, a basement house here is the standard $800 to $1,500 job, while a mobile home or crawlspace house usually runs $1,500 to $3,000 because of the membrane work. Full ranges on the cost page.

Where we work in Hellam Township

That covers the countryside around Wrightsville and the river corridor along the Susquehanna. The township is crossed by U.S. 30 on its way to the Wrightsville bridge. Public schools here are part of the Eastern York School District. The township dates to 1739. The Mifflin House, a documented Underground Railroad stop, is here, as is the Codorus Forge and Furnace Historic District.

Installers must hold a PA DEP radon mitigation certification (how to check).

Common questions

Is radon a problem in Hellam Township?

Yes. PA DEP has 5,376 tests on record from the ZIP codes covering Hellam Township, and 53.7% of them came back at or above the EPA's 4.0 pCi/L action level. 14.8% were at 20 pCi/L or more. The county-wide rate is 52.5%.

What is the average radon level in ZIP 17406?

The median of 4,025 PA DEP tests in ZIP 17406 is 4.3 pCi/L and the mean is 11.4 pCi/L. A mean that far above the median means a long tail of very high readings, topping out at 410 pCi/L.

Should I test my well water too if I live in Hellam Township?

If your house is on a private well, yes. USGS found some of the highest groundwater radon in Pennsylvania in the Peters Creek Schist that underlies this part of the county. Water radon is tested and treated separately from air radon. See radon and well water.

Nearby

Springettsbury Township 54.1%, Windsor Township 57.2%, East Manchester Township 50.6%. Share of PA DEP tests at or above 4.0 pCi/L, against 53.7% here.