Pennsylvania: basement moisture and foundation risk by county
67 counties, ranked by our combined index. Highest combined risk is Butler County (47), lowest is Clearfield County (30). The worst soil for foundation cracks specifically is in Lancaster County.
| County | Index | Moisture | Cracks | Water table | Region |
|---|---|---|---|---|---|
| Butler County | 47 | 37 | 48 | 66 | Appalachian Plateau |
| Bucks County | 45 | 34 | 60 | 46 | Piedmont |
| Montgomery County | 45 | 37 | 56 | 46 | Piedmont |
| Lycoming County | 44 | 36 | 53 | 46 | Appalachian Plateau |
| Schuylkill County | 44 | 35 | 56 | 46 | Ridge and Valley |
| Centre County | 43 | 36 | 52 | 46 | Ridge and Valley |
| Montour County | 42 | 35 | 50 | 46 | Ridge and Valley |
| Philadelphia County | 42 | 38 | 46 | 46 | Piedmont |
| Berks County | 41 | 38 | 42 | 46 | Piedmont |
| Clarion County | 41 | 36 | 45 | 46 | Appalachian Plateau |
| Clinton County | 41 | 34 | 47 | 46 | Ridge and Valley |
| Cumberland County | 41 | 36 | 55 | 30 | Ridge and Valley |
| Northampton County | 41 | 37 | 55 | 30 | Ridge and Valley |
| Venango County | 41 | 38 | 27 | 66 | Appalachian Plateau |
| Beaver County | 40 | 38 | 39 | 46 | Appalachian Plateau |
| Bradford County | 40 | 37 | 52 | 30 | Appalachian Plateau |
| Lancaster County | 40 | 36 | 63 | 16 | Piedmont |
| McKean County | 40 | 38 | 39 | 46 | Appalachian Plateau |
| Northumberland County | 40 | 37 | 50 | 30 | Ridge and Valley |
| Wyoming County | 40 | 36 | 42 | 46 | Appalachian Plateau |
| York County | 40 | 36 | 54 | 30 | Ridge and Valley |
| Columbia County | 39 | 37 | 37 | 46 | Ridge and Valley |
| Erie County | 39 | 38 | 36 | 46 | Appalachian Plateau |
| Greene County | 39 | 38 | 46 | 30 | Appalachian Plateau |
| Huntingdon County | 39 | 34 | 40 | 46 | Ridge and Valley |
| Lebanon County | 39 | 36 | 49 | 30 | Piedmont |
| Mifflin County | 39 | 36 | 51 | 30 | Ridge and Valley |
| Pike County | 39 | 36 | 51 | 30 | Appalachian Plateau |
| Westmoreland County | 39 | 35 | 52 | 30 | Appalachian Plateau |
| Armstrong County | 38 | 37 | 44 | 30 | Appalachian Plateau |
| Blair County | 38 | 37 | 44 | 30 | Ridge and Valley |
| Forest County | 38 | 34 | 48 | 30 | Appalachian Plateau |
| Sullivan County | 38 | 35 | 47 | 30 | Appalachian Plateau |
| Union County | 38 | 36 | 36 | 46 | Ridge and Valley |
| Elk County | 37 | 34 | 47 | 30 | Appalachian Plateau |
| Fulton County | 37 | 36 | 43 | 30 | Ridge and Valley |
| Indiana County | 37 | 35 | 44 | 30 | Appalachian Plateau |
| Jefferson County | 37 | 38 | 42 | 30 | Appalachian Plateau |
| Susquehanna County | 37 | 36 | 43 | 30 | Appalachian Plateau |
| Adams County | 36 | 33 | 34 | 46 | Ridge and Valley |
| Cameron County | 36 | 36 | 29 | 46 | Appalachian Plateau |
| Carbon County | 36 | 33 | 46 | 30 | Ridge and Valley |
| Lawrence County | 36 | 36 | 30 | 46 | Appalachian Plateau |
| Luzerne County | 36 | 33 | 43 | 30 | Ridge and Valley |
| Potter County | 36 | 36 | 29 | 46 | Appalachian Plateau |
| Tioga County | 36 | 35 | 42 | 30 | Appalachian Plateau |
| Warren County | 36 | 36 | 39 | 30 | Appalachian Plateau |
| Cambria County | 35 | 36 | 38 | 30 | Ridge and Valley |
| Delaware County | 35 | 35 | 40 | 30 | Piedmont |
| Monroe County | 35 | 35 | 39 | 30 | Ridge and Valley |
| Washington County | 35 | 36 | 25 | 46 | Appalachian Plateau |
| Allegheny County | 34 | 34 | 25 | 46 | Appalachian Plateau |
| Bedford County | 34 | 33 | 37 | 30 | Ridge and Valley |
| Chester County | 34 | 34 | 37 | 30 | Piedmont |
| Dauphin County | 34 | 33 | 37 | 30 | Ridge and Valley |
| Fayette County | 34 | 36 | 43 | 16 | Appalachian Plateau |
| Franklin County | 34 | 33 | 49 | 16 | Ridge and Valley |
| Lackawanna County | 34 | 34 | 48 | 16 | Appalachian Plateau |
| Lehigh County | 34 | 34 | 36 | 30 | Ridge and Valley |
| Crawford County | 33 | 34 | 44 | 16 | Appalachian Plateau |
| Snyder County | 33 | 37 | 29 | 30 | Ridge and Valley |
| Somerset County | 33 | 37 | 30 | 30 | Appalachian Plateau |
| Mercer County | 32 | 37 | 38 | 16 | Appalachian Plateau |
| Perry County | 32 | 35 | 39 | 16 | Ridge and Valley |
| Wayne County | 32 | 35 | 29 | 30 | Appalachian Plateau |
| Clearfield County | 30 | 37 | 30 | 16 | Ridge and Valley |
| Juniata County | 30 | 37 | 30 | 16 | Ridge and Valley |
Values from USDA NRCS SSURGO where available, otherwise our regional model — each county page states which. Methodology.
The physiographic regions inside Pennsylvania
State lines are political; soil follows geology. These are the distinct ground types inside Pennsylvania and why each behaves the way it does.
Appalachian Plateau
Water travels over bedrock under a thin skin of colluvium. A house cut into a hillside has an entire catchment behind its uphill wall — what decides the outcome here is a daylight drain, not a coating.
32 counties: Allegheny County, Armstrong County, Beaver County, Bradford County, Butler County, Cameron County, Clarion County, Crawford County, Elk County, Erie County, Fayette County, Forest County, Greene County, Indiana County, Jefferson County, Lackawanna County, Lawrence County, Lycoming County, McKean County, Mercer County, Pike County, Potter County, Somerset County, Sullivan County, Susquehanna County, Tioga County, Venango County, Warren County, Washington County, Wayne County, Westmoreland County, Wyoming County
Ridge and Valley
Limestone valleys mean karst: permeability is excellent until it is not. Sinkhole activity is an underrated cause of foundation failure here.
27 counties: Adams County, Bedford County, Blair County, Cambria County, Carbon County, Centre County, Clearfield County, Clinton County, Columbia County, Cumberland County, Dauphin County, Franklin County, Fulton County, Huntingdon County, Juniata County, Lehigh County, Luzerne County, Mifflin County, Monroe County, Montour County, Northampton County, Northumberland County, Perry County, Schuylkill County, Snyder County, Union County, York County
Piedmont
Saprolite is weathered rock that keeps its structure, so water moves through it along relict joints unpredictably. The Triassic basins inside the Piedmont are islands of strongly expansive clay.
8 counties: Berks County, Bucks County, Chester County, Delaware County, Lancaster County, Lebanon County, Montgomery County, Philadelphia County
Page data updated