Sinkhole risk in Philadelphia County, PA: No soluble rock mapped
No soluble rock mapped
No soluble bedrock mapped.
- On soluble rock
- 0%
- At or near the surface
- 0%
- Buried under cover
- 0%
What to do about a house in Philadelphia County
No soluble bedrock is mapped here, so natural sinkholes are unlikely. Collapses from broken pipes or old mines are a separate risk.
Across 134 square miles, under one square mile of Philadelphia County maps onto soluble rock. With about 1,573,916 residents (11,717 per square mile), most of the county is built up, so a mapped unit is likely to sit under somebody's street. The figures come from 467 map points about 0.5 miles apart, so a pocket smaller than that can be missed or overstated.
Read next: how these percentages are measured, and the warning signs that apply anywhere.
Counties around Philadelphia County
The nearest county rated sinkhole country is Union County, PA, about 121 miles northwest. 1 of the 6 closest counties land in the same band; the ground changes quickly around here.
- Delaware County, PA 15 mi southwest · 0% at surface
- Camden County, NJ 17 mi southeast · 6% at surface
- Montgomery County, PA 19 mi northwest · 5% at surface
- Gloucester County, NJ 20 mi south · 9% at surface
- Bucks County, PA 23 mi north · 2% at surface
- Burlington County, NJ 27 mi east · 4% at surface
Against the rest of Pennsylvania
Philadelphia County ranks 59 of 67 in Pennsylvania for soluble rock at the surface, and sits above 0% of US counties on that measure.
- Union County 53%
- Cumberland County 48%
- Lancaster County 46%
- Juniata County 45%
- Mifflin County 45%