Township, York County

Radon Mitigation in Hopewell Township, PA

Updated September 30, 2026

Hopewell Township is rural southern York County, surrounding Stewartstown near the Maryland line. Almost every home here is detached and owner-occupied. Its main ZIP code, 17363, has 2,814 PA DEP tests on record, a median of 6.9 pCi/L, and 64% at or above the action level. First-floor readings are high here too, with a median of 4.5 pCi/L.

What the PA DEP test records show for Hopewell Township

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

• ZIP 17363 (about 86% of Hopewell Township's land): median 6.9 pCi/L across 2,814 tests, 21.4% at 20 or higher, top reading 333. Basement median 7.3, first floor 4.5.
• ZIP 17349 (about 11% of Hopewell Township's land): median 4.3 pCi/L across 2,730 tests, 11.2% at 20 or higher, top reading 240. Basement median 4.7, first floor 2.8.

The spread inside Hopewell Township runs from 52% of tests high in 17349 to 63.8% in 17363.

The share that matters most is the 20+ column. 16.4% 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 333 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 17363, basement tests have a median of 7.3 pCi/L, while tests taken on the first floor have a median of 4.5 pCi/L (222 first-floor tests). The gap is smaller than in most of the county, which means readings upstairs here are not much of a relief from the basement number.

This matters for what you test. The PA DEP and EPA guidance is to test the lowest level you use or could use as living space. If the basement is finished, or might be someday, test it there. A finished rec room at 7.3 pCi/L is a different decision from an unfinished storage basement you rarely stand in.

Radon results by decade in ZIP 17363

The share peaked in the 2000s at 69.7% and sits at 56.4% 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 Hopewell Township has not changed. 543 tests have been logged in 17363 since 2020, so people here are still testing.

The ground under Hopewell Township

Hopewell is in the Piedmont Upland, in the belt of schist and related metamorphic rock that covers southern York County. The Peters Creek Schist and related units are mapped in this part of the county, although exact boundaries inside the township aren't confirmed.

In a USGS study of 16 Pennsylvania rock units, the Peters Creek Schist had the highest median groundwater radon, and USGS flagged it as the unit with the highest potential exposure from both water and indoor air. For a house on a well out here, testing the water as well as the air is reasonable.

Housing in Hopewell Township and what it means for a system

Census Bureau, American Community Survey 2020 to 2024:

88.1% of homes in Hopewell 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, most houses in Hopewell Township are the standard $800 to $1,500 sub-slab job, with block walls or a second suction point pushing toward $2,500. Full ranges on the cost page.

Where we work in Hopewell Township

That covers the countryside around Stewartstown. Route 24 runs through the township. Public schools here are part of the South Eastern School District. Hopewell dates to 1767, and three bridges from the old Stewartstown Railroad are on the National Register.

Installers must hold a PA DEP radon mitigation certification (how to check), and permit questions go to the township office at www.hopewelltownship.com.

Common questions

Is radon a problem in Hopewell Township?

Yes. PA DEP has 5,544 tests on record from the ZIP codes covering Hopewell Township, and 58% of them came back at or above the EPA's 4.0 pCi/L action level. 16.4% were at 20 pCi/L or more. The county-wide rate is 52.5%.

What is the average radon level in ZIP 17363?

The median of 2,814 PA DEP tests in ZIP 17363 is 6.9 pCi/L and the mean is 14.3 pCi/L. A mean that far above the median means a long tail of very high readings, topping out at 333 pCi/L.

Is the first floor safe if the basement tests high?

Not necessarily here. In ZIP 17363, first-floor tests have a median of 4.5 pCi/L, above the action level on their own. If the basement is high, test upstairs too before assuming the living space is fine.

Nearby

Shrewsbury Township 55.5%, Dallastown 65.7%. Share of PA DEP tests at or above 4.0 pCi/L, against 58% here.