Under Pennsylvania's Real Estate Seller Disclosure Law (68 Pa. C.S. § 7301), sellers must disclose known radon test results to buyers. If results exceed the EPA action level of 4 pCi/L, buyers may negotiate mitigation as a condition of sale. DEP-certified mitigation typically takes 1–2 days and costs $800–$1,500.
Radon and Home Sales in Pennsylvania: Disclosure, Contingencies & Buyer Rights (2026)
Pennsylvania has two laws a real estate transaction has to contend with when a known radon condition exists: the Real Estate Seller Disclosure Law (68 Pa. C.S. § 7301) and the EPA's 4.0 pCi/L action level. The disclosure law governs what must be shared; the EPA threshold governs what typically triggers action. This guide covers both, plus the timelines, negotiation patterns, and post-mitigation protocol that govern radon in Pennsylvania closings.
Pennsylvania Radon Disclosure Law
What Sellers Are Required to Disclose
Pennsylvania's Real Estate Seller Disclosure Law (68 Pa. C.S. § 7301 et seq.) requires sellers of residential real property to complete a Seller's Property Disclosure Statement covering material defects and environmental conditions — including radon. Sellers must disclose:
- Any known radon test results, including date, methodology, and measured concentration
- The existence of any installed radon mitigation system, make and model if known
- Post-mitigation test results if available
- Any known defects or failures of an existing mitigation system
Section 7301 is a disclosure statute, not a testing statute. A seller who has never tested is under no obligation to do so before listing — the legal duty attaches only to results they already have. Knowing misrepresentation or omission of a disclosed material fact exposes the seller to statutory damages under § 7311.
When Disclosure Does Not Apply
Section 7301 carves out specific exemptions from the disclosure requirement. The most common in practice:
- New construction transferred by the builder to the first occupant is exempt — the builder has no occupancy history from which to have radon knowledge. Radon-resistant new construction (RRNC) requirements in Zone 1 counties still apply.
- Foreclosure and sheriff's sale transfers are exempt because the transferring entity (lender or court) lacks personal knowledge of property conditions.
- Transfers between co-owners, transfers in trust, and transfers incident to divorce are generally exempt.
Exemption from § 7301 does not exempt the transaction from the EPA action level or from a buyer's right to test under the inspection contingency. Foreclosure buyers in particular should test — distressed properties in Zone 1 counties rarely have testing history.
Who Pays for Radon Mitigation in a PA Home Sale
Buyer-Requested Contingency Language
The standard Pennsylvania Association of Realtors (PAR) Agreement of Sale includes a radon testing contingency that buyers should activate on any transaction in a Zone 1 or Zone 2 county. The contingency typically specifies: the testing window (48–96 hours during the inspection period), the testing standard (DEP-certified CRM or short-term charcoal canister under ANSI-AARST protocol), and the action threshold (4.0 pCi/L).
If the test result exceeds the action threshold, the buyer may: request seller-funded mitigation and retest as a condition of closing, negotiate a price reduction equivalent to mitigation cost, walk away under the inspection contingency without penalty, or proceed with the purchase unchanged. Most Zone 1 transactions settle on seller-funded mitigation.
Seller-Paid Mitigation as a Closing Condition
When sellers agree to fund mitigation, the work is typically written into the purchase agreement as a condition precedent to closing. The contract should specify: (1) the work must be performed by a DEP-certified contractor under PA Code Title 25, Chapter 240; (2) the system must meet ANSI-AARST CCAH residential mitigation standards; (3) a post-mitigation test must confirm levels below 4.0 pCi/L; and (4) the seller will provide installation and test documentation prior to closing.
An alternative structure — particularly on tight timelines — is a post-closing escrow. The seller funds the estimated mitigation cost into a title company escrow; the buyer completes the work within a defined window after closing and is reimbursed from escrow against paid invoices.
Typical Cost Range in Pennsylvania
Standard residential ASD systems in Pennsylvania cost $800–$1,500 for a single-suction-point installation on a poured-concrete basement. Complex foundations — hollow concrete block, stone, slab-on-grade — push toward the upper end of the statewide range ($843–$2,529). Post-mitigation testing adds $150–$300 if not included. For a full cost breakdown by foundation type and city market, see the Pennsylvania radon mitigation cost guide.
The EPA 4 pCi/L Action Level and Your Closing
What Happens When Test Results Exceed 4 pCi/L
The EPA's 4.0 pCi/L action level is not a safety threshold — it is the concentration above which the EPA recommends mitigation based on lung cancer risk estimates. In Pennsylvania transactions, 4.0 pCi/L functions as the de facto contract trigger: a result at or above that level almost always initiates a negotiation, while a result below it rarely does. Results between 2.0 and 3.9 pCi/L are sometimes renegotiated at the buyer's discretion — the EPA's “consideration level” — but not as a matter of standard practice.
A single short-term test above the action level is sufficient to trigger mitigation. Industry guidance does not require follow-up long-term testing when initial short-term results are clearly elevated; the pragmatic move is to mitigate and retest.
Retesting After Mitigation
Post-mitigation testing protocol under ANSI/AARST standards requires a minimum 24-hour closed-house test, with 48 hours recommended for higher confidence. The test must be performed using a continuous radon monitor (CRM) or a charcoal canister placed in the lowest livable area, under closed-house conditions (windows closed, HVAC operating normally). For real estate disclosure purposes, the post-mitigation test should be performed by a DEP-certified Radon Testing Contractor (RTC) separate from the installing mitigator — not by the same person who did the installation.
How Long Does Radon Mitigation Take Before Closing
Mitigation timeline components, assuming a standard residential ASD system:
- ASD installation: 1–2 days. Most single-suction-point jobs are completed in 4–8 hours; multi-point or complex-foundation installations may require a second day.
- Post-mitigation test: minimum 24 hours under closed-house conditions; 48 hours is recommended for higher confidence in a single reading.
- Total timeline impact on closing: 3–5 business days if negotiated proactively during the inspection period. Procurement of a DEP-certified contractor on tight timelines can be the limiting factor, particularly in Zone 1 counties during peak season (March–October).
For closings scheduled less than one week after a mitigation contingency is triggered, a post-closing escrow is often the cleaner mechanism. The buyer takes possession, the installed system is scheduled at the buyer's convenience, and the seller-funded escrow covers the invoiced cost.
SB 760 and Community Radon Awareness
Pennsylvania Senate Bill 760, which mandates radon testing in public school buildings in EPA Zone 1 counties during the 2026–2027 academic year, will substantially raise community awareness of radon in exactly the counties where residential radon risk is highest. Test results from school buildings will be publicly reported, covered in local media, and discussed at school board meetings — a material information event for homeowners and buyers. The practical effect for real estate: buyer diligence on radon in Zone 1 counties will become more consistent, radon testing contingencies will be activated more reliably, and sellers who list without current test documentation will face more consistent buyer-side requests for testing during the inspection period. For full SB 760 compliance details, see the Pennsylvania Radon Compliance 2026 guide.
Frequently Asked Questions
No. Pennsylvania's Real Estate Seller Disclosure Law (68 Pa. C.S. § 7301) is a disclosure mandate, not a testing mandate. Sellers must disclose any known radon test results and any installed mitigation system — but they are not legally required to test before listing. Buyers should always include a radon testing contingency in the purchase agreement.
The EPA action level of 4.0 pCi/L is the threshold at which mitigation is recommended. Results at or above 4.0 pCi/L typically trigger a buyer's request for seller-funded mitigation as a condition of closing. Results between 2.0 and 3.9 pCi/L warrant a follow-up long-term test. There is no legal "fail" — only the EPA-recommended action threshold.
Yes. Sellers are not legally required to mitigate a radon condition. However, refusal typically results in the buyer either walking away under the inspection contingency, requesting a price reduction equivalent to mitigation cost, or negotiating a post-closing escrow for the work. Pennsylvania's Zone 1 counties see radon mitigation contingencies in the majority of transactions — refusal is increasingly uncommon because the typical $800–$1,500 cost is minor relative to transaction value.
A standard active sub-slab depressurization (ASD) system can be installed in 1–2 days. A minimum 24-hour post-mitigation test is required to confirm levels below 4.0 pCi/L — 48 hours is recommended for higher confidence. If negotiated early in the inspection period, the total timeline impact on closing is typically 3–5 business days.
Radon testing cost is almost always paid by the buyer as part of the inspection contingency. Professional DEP-certified CRM testing runs $150–$350. If the result exceeds 4.0 pCi/L, the buyer may request seller-funded mitigation ($800–$1,500) and a post-mitigation retest as a condition of closing. The seller may counter with a price reduction in lieu of mitigation.
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PA Radon Hub is an independent informational resource. We are not a real estate attorney and this is not legal advice. We connect homeowners with DEP-certified radon professionals.