Radon Disclosure Requirements When Selling a Home in Pennsylvania

Pennsylvania Has Two Laws That Govern Radon Disclosure

Radon disclosure in Pennsylvania is grounded in two separate statutes that work together. The Pennsylvania Radon Certification Act (Act 73 of 1988) established DEP certification requirements for radon professionals and created the regulatory framework for testing and mitigation. The Real Estate Seller Disclosure Law (Act 49 of 1996) requires sellers to disclose all known material defects in a property, including radon conditions, on the state-mandated Seller’s Property Disclosure Statement.

Together, these laws mean that if you have tested your home for radon and received results, you must disclose those results. If a mitigation system has been installed, you must disclose its existence, history, and documentation. What you cannot do is omit known radon information from the disclosure form. Sellers who conceal material defects face fraud and misrepresentation claims after closing, and Pennsylvania courts have consistently treated undisclosed radon as a material defect.

The Seller’s Property Disclosure Statement: The Radon Section

Pennsylvania's Seller’s Property Disclosure Statement is a standardized, state-mandated form required in all residential real estate transactions. The form includes a specific radon section that asks sellers to disclose:

Known test results: Every radon test result you have, including professional tests and DIY tests, with approximate dates and results in pCi/L.
Mitigation history: Whether a mitigation system has ever been installed, who installed it, and when.
Post-mitigation testing: Test results taken after any mitigation system was installed, showing whether the system achieved acceptable levels.
System condition: Any known defects or changes in mitigation system performance.

The standard is what you know. Pennsylvania does not require testing before you sell. If you have never tested and have no reason to believe a radon issue exists, you mark the form accordingly. But if you have test results on file, those must be disclosed regardless of when the test was conducted or how old the result is.

The Reading Prong: Why Radon Disclosure Is Especially Critical

The Reading Prong is the most notorious radon hotspot in the United States. This geological formation runs southwest to northeast through Bucks, Montgomery, Berks, Lehigh, and Northampton counties and is composed of Precambrian metamorphic and igneous rocks that contain elevated uranium concentrations. Radon released from this bedrock diffuses upward into basements and living spaces at rates far exceeding national averages.

The Reading Prong became nationally known in 1984 when Stanley Watras, an engineer at the Limerick Nuclear Power Plant in Berks County, repeatedly triggered radiation alarms upon arriving at work. Investigators discovered he was carrying radon contamination from his Boyertown home, where levels measured above 2,700 pCi/L. That discovery launched the national radon awareness movement and prompted the EPA to develop its radon action program.

Pre-mitigation results of 10 to 30 pCi/L are common across the Reading Prong counties. Results above 50 pCi/L are not rare. Buyers who have shopped in this market are radon-aware and expect to see either a mitigation system in place or documentation of a recent clean test. Real estate agents in Bucks, Montgomery, Berks, and Lehigh counties treat radon testing as a standard part of every transaction, not an unusual request.

For sellers in this region, the strategic calculation is clear: test before listing, mitigate if above 4 pCi/L, and present a system with post-mitigation documentation under 2 pCi/L. This converts radon from a negotiation liability into a non-issue. A $1,000 to $1,800 mitigation system is far less costly than a buyer-driven price reduction or a failed deal.

Lehigh Valley and Allentown/Bethlehem

Lehigh and Northampton counties sit directly on the Reading Prong and share its radon characteristics. Allentown, Bethlehem, and Easton buyers treat radon testing as a standard inspection item. Sellers in the Lehigh Valley should apply the same pre-listing strategy as those in Bucks and Montgomery counties: test, mitigate if needed, and document everything. Radon is a known variable in this market and buyers come prepared to address it.

Philadelphia Suburbs

Montgomery, Bucks, and Delaware counties are among the most active radon testing markets in the state. The Philadelphia suburban market has a high volume of transactions and buyers who are represented by experienced agents and inspectors familiar with regional radon conditions. Chester County sits on the eastern edge of the Piedmont formation and has significant radon variability by municipality. Testing before listing is standard advice from most real estate attorneys operating in the Philadelphia suburbs.

Pittsburgh Metro

Allegheny County and the surrounding Pittsburgh metro sit on Devonian shale and coal measures that produce elevated but generally lower radon levels than the Reading Prong. Radon testing is common in Pittsburgh transactions, and results above 4 pCi/L occur regularly. Sellers in Pittsburgh metro should disclose any known radon history and anticipate buyer requests for testing, but pre-mitigation results in the 4 to 12 pCi/L range are more typical than the extreme levels seen in southeastern Pennsylvania.

Pocono Vacation Homes

The Pocono Mountain region in Monroe, Pike, Wayne, and Carbon counties presents a specific disclosure challenge. Vacation and seasonal properties are often untested and unmonitored for long periods, during which radon can accumulate. Buyers of Pocono vacation homes, investment properties, and seasonal rentals should insist on professional testing during their inspection period. Sellers of seasonal properties who have never tested cannot disclose what they do not know, but should understand that uninspected vacation homes carry additional due diligence expectations from buyers and their attorneys.

What Buyers Can Do Under Pennsylvania Law

Standard Pennsylvania real estate contracts include an inspection contingency that gives buyers the right to commission a professional radon test during the inspection period. If the test returns a result above 4 pCi/L, buyers can:

Request that the seller install a DEP-certified mitigation system before closing
Negotiate a price reduction or closing credit to cover mitigation costs
Accept the result and install mitigation after closing
Terminate the contract under the inspection contingency if no resolution is reached

For real estate transactions in Pennsylvania, the radon test must be conducted by a DEP-certified radon measurement professional. DIY tests are not accepted for real estate purposes. The test typically runs 48 hours and is scheduled during the inspection window. Results come back within a day or two of the device being retrieved, fitting comfortably within a standard inspection period.

Seller Strategy: Step by Step

Here is the recommended approach for Pennsylvania sellers who want to handle radon cleanly:

Test before listing. Hire a DEP-certified radon measurement professional. Cost: $100 to $300. If you are in the Reading Prong region, do this before you set a listing price.
If results are below 4 pCi/L, document the test with date, tester name, certification number, and result. Attach it to your disclosure. Buyers will accept clean documentation without further negotiation.
If results are between 4 and 10 pCi/L, install a sub-slab depressurization system immediately. Cost: $800 to $1,800 for most PA homes. Obtain a post-mitigation test showing levels below 2 pCi/L and include that documentation with your disclosure.
If results are above 10 pCi/L, same action, but prioritize speed and use a contractor with experience on high-level homes. In the Reading Prong, contractors handle these cases routinely. A documented result under 2 pCi/L after mitigation removes the issue from the transaction entirely.
Transfer the warranty. Most Pennsylvania mitigation contractors offer a warranty on their systems. Transfer it to the buyer at closing. This adds tangible value and reduces post-sale questions.

Find Certified Radon Professionals in Pennsylvania

Whether you need a pre-listing test, a mitigation system installed before closing, or updated documentation for a buyer’s inspection, our directory lists certified radon professionals in Pennsylvania who hold current DEP certification under Act 73. You can search by county to find testers and mitigators serving your area, from the Reading Prong counties to Pittsburgh, the Lehigh Valley, and the Pocono region.

Frequently Asked Questions

Does Pennsylvania require radon disclosure when selling a home?

Yes. Under Pennsylvania's Real Estate Seller Disclosure Law (Act 49 of 1996), sellers must disclose all known radon test results, any history of mitigation, and the presence of a mitigation system on the state-mandated Seller's Property Disclosure Statement. Failure to disclose known material defects, including radon, exposes sellers to legal liability after closing.

Is a seller required to test for radon before listing in Pennsylvania?

No. Pennsylvania law requires disclosure of what you know, not a pre-listing test. But if you are in Bucks, Montgomery, Berks, Lehigh, or Northampton County, buyers will almost certainly request a test during inspection. Testing before you list gives you control over timing and results, and lets you mitigate proactively if needed.

What radon levels are common in the Reading Prong counties?

Very high levels. Pre-mitigation results of 10 to 30 pCi/L are common in Bucks, Montgomery, Berks, and Lehigh counties, and levels above 50 pCi/L have been documented. The national average indoor radon level is 1.3 pCi/L. If you are selling in the Reading Prong, assume buyers will expect to see radon addressed.

Does a mitigation system hurt a home sale in Pennsylvania?

No, particularly in the Reading Prong region. Buyers in Bucks, Montgomery, Berks, and Lehigh counties are accustomed to seeing mitigation systems. A system that is working, documented with a post-mitigation test below 2 pCi/L, and covered by a transferable warranty removes radon as a negotiation point entirely. It is a selling advantage, not a liability.

What should I disclose if my home already has a mitigation system?

Disclose the installation date, the name and DEP certification number of the installer, the original post-mitigation test result, any subsequent test results, and any warranty documentation. Confirm the fan is running and the manometer shows negative pressure before listing. A system that has not been re-tested in two or more years is a yellow flag for buyers; schedule a fresh test so you have current documentation.