Radon in Allegheny County, Pennsylvania

What Radon Mitigation Costs in Allegheny County, and How to Get It Done

Active sub-slab depressurization systems in the Pittsburgh area run $950–$2,400 installed. The spread reflects the county's housing mix more than its radon levels: a mid-century suburban poured-concrete basement is a routine single-suction installation, while a pre-war city rowhouse or a hillside home with stepped foundations and partial crawlspace may need multi-point suction or encapsulation work. A high radon reading does not by itself raise the price; foundation type does.

Allegheny is one of the better-supplied counties in Pennsylvania for certified mitigation work: five DEP-certified firms hold business addresses inside the county, with more serving it from Beaver, Westmoreland, and Washington. That depth of supply is a homeowner's advantage — you can reasonably ask for a certification number, a proposed suction-point layout, and a post-mitigation verification plan before committing, and compare more than one quote. Certification under 25 Pa. Code § 240 is mandatory for anyone performing radon testing or mitigation in the Commonwealth; confirm the number is current in the PA DEP Radon Services Directory before signing.

The reason to test in the first place is that a county figure cannot describe an individual home. Of Allegheny's 310,884 basement tests, 34% measured 4.0 pCi/L or higher — about one test in three — across 110 ZIP codes and widely varying terrain. A DEP-certified contractor interviewed by PA Radon Hub reports Ross Township and Allison Park test consistently elevated. The county number tells you what the county looks like; only a test tells you what your home is.

EPA Zone 1 and What the Test Record Shows

Allegheny County is classified EPA Zone 1, the highest radon-potential classification, which predicts an average indoor radon level above 4.0 pCi/L. In the PA DEP record, 34% of 310,884 basement tests measured 4.0 pCi/L or higher and the median result is 2.7 pCi/L. The zone is a prediction for the county as a whole; the test record is a set of measurements.

The EPA Map of Radon Zones is a 1993 predictive classification built from geology, aerial radiometric survey, soil permeability, and foundation type. The PA DEP figures here are measured results from tests ending between January 1986 and July 2026. A predictive model and four decades of measurement are answering different questions.

By share of basement tests at or above 4.0 pCi/L, Allegheny ranks 55th highest of 67 counties, 3 points below the 37% statewide share. Of the four counties it borders, Beaver is at 49%, Butler 47%, and Westmoreland 40%; Washington, at 34%, is level with Allegheny. Allegheny is a lower-reading county in a higher-reading region.

None of that makes an individual Allegheny home safe by default. About one basement test in three reached the action level. The county number tells you what the county looks like; it tells you nothing about a specific address.

Conemaugh Group Bedrock and Pittsburgh Housing Stock

Allegheny sits on Appalachian Plateau bedrock — the coal-bearing Conemaugh Group, a cyclic sedimentary stack of sandstone, shale, and coal. Cyclic layering means repeated contacts between rock types of different permeability, and fractures running through that stack open soil-gas pathways into the structures above.

The housing stock is old and concentrated. Median year built for owner-occupied housing is 1957 countywide and 1942 in the city of Pittsburgh — a pre-war urban core surrounded by mid-century suburban build-out, across a county of 1,231,814 residents with a median owner-occupied home value of $216,700.

Terrain matters as much as age here. A DEP-certified mitigation contractor interviewed by PA Radon Hub reports that Ross Township and Allison Park test consistently elevated — a reminder that a county figure covers steep, geologically varied ground, not a uniform condition. Hillside neighborhoods with deep-cut foundations behave differently from valley-floor construction a few miles away.

Five DEP-certified mitigation firms hold business addresses in Allegheny County, the largest concentration among the counties in this region and a practical advantage for scheduling both testing and installation.

Measured Radon Data for Allegheny County

Source: PA Department of Environmental Protection, Radon Test Results, data.pa.gov. Tests through July 2026. Retrieved September 29, 2026. 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.

The value of this grid is its denominator. 310,884 basement tests and 21,970 first-floor tests make Allegheny the largest county sample in Pennsylvania, large enough that the shares and medians above can be used as a reference point rather than an indication.

Cities and Boroughs in Allegheny County

Pittsburgh is the Allegheny County municipality with its own PA Radon Hub page. That page holds the Pittsburgh-area figures, the local cost range, and connections to DEP-certified professionals serving the county.

Adjacent Counties

Three of the four counties Allegheny borders have a higher share of basement tests at or above 4.0 pCi/L: Beaver at 49%, Butler at 47%, and Westmoreland at 40%. Washington, at 34%, is level with Allegheny. If you are weighing a property in a neighboring county against one here, the measured numbers are on these pages.

Comparing radon risk across the wider Commonwealth? Browse All 67 Pennsylvania county radon pages for EPA zone classification and measured basement averages statewide.

Testing and Mitigation Options in Allegheny County

Frequently Asked Questions

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