Pennsylvania

Pennsylvania is one of the highest-radon states in the country. In the state’s own records, 33.9% of about 3.3 million home radon tests came back at or above the EPA action level of 4 pCi/L ^[PA-4]. (RadonCosts analysis of PA DEP data, residential and unspecified tests, 1986–Oct 2026. These are homes that chose to test, not a random sample.)

RadonCosts lists 97 radon mitigation companies for Pennsylvania. 92 of them appear on the PA DEP list of certified mitigators dated Oct 1, 2026 ^[PA-3], and the rest hold NRPP or NRSB mitigation certification. 14 are based in neighboring states but hold Pennsylvania certification.

Pennsylvania at a glance

Pennsylvania radon rules

• Certification: nobody may mitigate radon in a Pennsylvania building, or advertise that they can, unless they hold DEP certification or work for a DEP-certified mitigation firm. Each certified firm must employ at least one certified individual in responsible charge of its mitigation work ^[PA-6]. DEP publishes the list of certified mitigators in its Radon Services Directory ^[PA-3].
• Post-mitigation test: DEP’s consumer guide says a post-mitigation test must be done within 30 days of installation, but no sooner than 24 hours after the system is running. The contractor must make sure that test is performed ^[PA-2].
• Real estate: Pennsylvania’s seller disclosure law requires the property disclosure statement to cover the “presence of hazardous substances” ^[PA-5]. Sellers should share any radon test results and mitigation paperwork. Testing isn’t required by law, but buyers commonly test during inspection.
• Check a credential: search the current PA DEP mitigator list by name or county. Every RadonCosts listing shows its DEP firm ID.

Radon by county: highest share of tests at 4 pCi/L or above

Largest counties: Allegheny 32.5% (Zone 1) · Montgomery 24.6% (Zone 1) · Bucks 25.6% (Zone 1) · Delaware 17.8% (Zone 1) · Lancaster 51.3% (Zone 1) · Chester 29.3% (Zone 1) · Philadelphia 10.8% (Zone 3) ^{[PA-4][EPA-5]}

Source: PA DEP radon test results, PA Open Data ^[PA-4]. Averages are arithmetic means, which a small number of very high results can pull up. “Tests on record” counts tests, not homes.

Even in lower-share counties such as Philadelphia, about 1 in 10 recorded tests was high. Test your own home.

Certified installers in Pennsylvania

Cities with the most listed companies: Allentown (4), Pittsburgh (3), then Harrisburg, Erie, Lebanon, Mechanicsburg and Phoenixville (2 each). Most PA companies serve several counties, so check service areas on each listing.

What radon mitigation costs in Pennsylvania

• PA DEP (2025): permanent systems “typically cost between $800 and $1,200” ^[PA-1].
• PA DEP consumer booklet (older): $500–$2,000, average about $1,000. Replacement fans run about $250–$350 installed ^[PA-2].
• National surveys: $805–$1,326, average $1,043 ^[ANGI].
• What PA installers post online: 3 of 33 PA-listed websites we could read state a mitigation-system price or price range (crawl Nov 2, 2026). The lowest figure each one posts has a median of $1,450 (range $1,350–$2,000). These are the companies’ own advertised figures, sometimes for a specific job type (for example new construction or activating a passive system). They aren’t quotes:
  • Rvs Radon Mitigation, LLC.: $1,350–$2,500 (source)
  • Accurate Radon Control INC: $1,450 (source)
  • Home Radon Pros: $2,000 (source)
• RadonCosts homeowner reports: not enough yet. Report what you paid.

Crawl spaces, several foundation sections, finished basements and interior pipe routes push prices toward the top of these ranges. See the cost guide.

FAQ

Does my installer need to be certified in Pennsylvania? Yes. Anyone mitigating radon in a Pennsylvania building needs DEP certification or must work for a certified firm ^[PA-6]. Check the firm ID on the DEP list.

What does a radon system cost in Pennsylvania? PA DEP puts typical systems at $800–$1,200 ^[PA-1]. Complex homes cost more.

My county is “Zone 3.” Do I need to test? Yes. About 1 in 10 recorded tests in Philadelphia were at or above 4 pCi/L ^[PA-4], and only a test tells you about your home ^[EPA-2].

Is DIY testing OK? For your own home, yes. A kit costs about $20–$30 ^[PA-1]. For a home sale, a DEP-certified tester avoids disputes.

Data: PA DEP certified mitigator list (Oct 1, 2026), NRPP and NRSB searches (Nov 2, 2026), PA DEP radon test data (PA Open Data, through Oct 2026), EPA radon zones (2024 data file), US Census 2024 estimates.