Pennsylvania — 6.2M metro

Radon in Philadelphia,
PA

Pennsylvania is the state with the most total radon-related lung cancer deaths in the US. Philadelphia's location near the Reading Prong — a uranium-rich geological formation — means elevated risk across much of the region, especially in Montgomery, Chester, and Bucks counties.

Risk Level

Very High Risk

3–8 pCi/L

Typical range (area avg.)

EPA action level: 4 pCi/L

Why Philadelphia Has Very High Risk Radon

The Reading Prong extends into southeastern Pennsylvania, bringing metamorphic and granitic rock formations that generate significant radon. While the city proper sits on sedimentary geology, the Pennsylvania DEP notes elevated risk in many Philadelphia-area counties.

Local Housing and Radon Risk

Philadelphia's row house stock — millions of narrow brick homes sharing walls — actually tends to have lower radon than detached homes with exposed foundations. However, the many attached single-family homes in the suburbs with full basements present standard risk.

Testing Advice for Philadelphia Residents

Pennsylvania DEP's radon program offers discounted test kits. The state also certifies radon testers and mitigators — always use a PA DEP-certified contractor for mitigation work.

How to Test Your Philadelphia Home

Step 1: Choose Your Test Type

For initial screening, a charcoal short-term test kit ($12–$25) placed for 48–96 hours provides a quick result. For the most accurate reading, a long-term alpha-track test ($20–$35) left in place for 90+ days accounts for seasonal variation — especially important in Philadelphia's climate.

Step 2: Place the Test Correctly

Test in your lowest livable level — basement if you have one, otherwise the first floor. Keep the test 20 inches from the floor, away from windows and exterior walls. Close windows and doors 12 hours before and during the test for accurate results.

Step 3: Interpret Your Results

Below 2 pCi/L: low concern, retest every 2 years. 2–4 pCi/L: consider mitigation, retest in 2 years. 4 pCi/L or higher: the EPA recommends mitigation. Above 8 pCi/L: prioritize mitigation promptly.

Step 4: Hire a Certified Mitigator if Needed

If your test result is at or above 4 pCi/L, hire a certified radon mitigator. In Pennsylvania, always verify your contractor's state certification. Sub-slab depressurization — the most effective mitigation method — typically costs $850–$1,500 installed in the Philadelphia area.

Frequently Asked Questions — Radon in Philadelphia

Is radon a real problem in Philadelphia?

Yes. Pennsylvania is the state with the most total radon-related lung cancer deaths in the US. Philadelphia's location near the Reading Prong — a uranium-rich geological formation — means elevated risk across much of the region, especially in Montgomery, Chester, and Bucks counties. The EPA recommends all homes be tested regardless of location — radon levels can vary significantly even between neighboring properties.

How much does radon mitigation cost in this area?

In the Philadelphia area, professional radon mitigation (sub-slab depressurization) typically costs $850–$1,500 installed. This is a one-time cost that reduces radon by 50–99%. The system requires minimal maintenance and a mitigator can typically complete the work in 3–5 hours.

Should I test if I have a new home?

Absolutely. New homes built with radon-resistant features still show elevated levels in testing — construction conditions and local geology vary too much to assume any home is safe. Test within the first year of occupancy, especially if your home has a basement.

Can I test radon myself, or do I need a professional?

DIY testing is reliable and recommended as a first step. Short-term kits ($12–$25) and long-term kits ($20–$35) are accurate when placed and returned correctly. Professional testing is only required for real estate transactions in some states. If your DIY test shows elevated levels, use a certified professional for both confirmation testing and mitigation.