Pennsylvania Radon Compliance 2026: Law, Disclosure, and Testing Standards
Pennsylvania does not require homeowners to test or mitigate radon, but sellers must disclose known radon results under 68 Pa.C.S. § 7303. The EPA action level is 4.0 pCi/L, and roughly 40% of Pennsylvania homes exceed it. Only PA DEP-certified professionals may legally install mitigation systems.
Is Radon Mitigation Required by Law in Pennsylvania?
Pennsylvania does not mandate radon mitigation for existing private homes, but the Indoor Radon Abatement Act (IRAA) establishes the EPA action level of 4 pCi/L as the federal remediation threshold. PA DEP enforces certification requirements for all contractors performing mitigation work under PA Code § 240.
What Does the Indoor Radon Abatement Act Require?
The federal Indoor Radon Abatement Act directs the EPA to reduce indoor radon levels to match outdoor concentrations, funds state radon programs, and requires public school testing. Pennsylvania administers its program through PA DEP's Radon Division, which certifies all testers, mitigators, and laboratories operating in the state.
What Are Pennsylvania's Radon Disclosure Rules When Selling a Home?
Pennsylvania requires sellers to disclose known radon conditions under the Real Estate Seller Disclosure Law (Act 49 of 1996). Sellers must complete the SPRDS form, which includes a radon section. If a test result exceeding 4 pCi/L exists, it must be disclosed. Buyers may request a radon inspection as a contract condition.
Includes county risk levels, disclosure obligations, and what to ask your DEP-certified inspector.
Download the Free Guide →Pennsylvania's radon legal framework rests on residential disclosure under 68 Pa.C.S. § 7301 et seq., with the seller's duty at § 7303. This guide explains what that statute requires and what it does not, covers DEP certification requirements for mitigation contractors, and clarifies what the EPA's 4.0 pCi/L action level means in practice for buyers and sellers.
The Reading Prong's uranium-bearing crystalline bedrock directly underlies or abuts eight of Pennsylvania's highest-risk counties. Northampton County and Lehigh County sit at the Prong's southeastern core, where Bethlehem, Easton, and Allentown consistently record among the highest residential radon measurements in the state. Berks County homes in Reading, Kutztown, and Hamburg sit on granite and phyllite with high natural uranium concentrations. Moving southwest, Montgomery County, Chester County, and Bucks County transition into Precambrian gneiss and Piedmont schist terrain with comparably elevated radon potential. York County and Cumberland County sit on carbonate and shale geology that produces radon through different but equally significant pathways. In all of these counties, PA DEP strongly recommends testing all homes regardless of age or construction type. Radon testing in York County is particularly important pre-listing because the karst transport mechanism produces variable but persistent above-action-level readings across municipal boundaries.
Pennsylvania's Highest-Risk Counties by Geology
Bethlehem and Easton record among PA’s highest residential radon averages.
Allentown sits directly on high-uranium bedrock with minimal soil buffer.
Reading, Kutztown, and Hamburg all sit on or near the Prong’s uranium core.
Dense suburban housing stock with high pre-mitigation radon test rates.
Phoenixville and the northern corridor sit on some of PA’s oldest crystalline bedrock.
Northern Bucks County shows elevated radon rates tied to subsurface Reading Prong geology.
Karst pathways allow rapid radon migration from bedrock into residential foundations.
Aging housing stock and Piedmont crystalline geology combine to elevate residential risk.
York and Hanover test above PA statewide averages across multiple housing vintages.
Carlisle, Mechanicsburg, and Shippensburg consistently exceed EPA action levels in testing.
PA Radon Hub maintains city-level radon data and DEP-certified contractor connections for all 10 of these counties. Use the DEP-certified contractor directory to find verified professionals in your county, or review county-level mitigation cost estimates before requesting quotes.
Radon Information by Pennsylvania County
Pennsylvania radon levels vary by geology and county. Find county-specific radon data and DEP-certified mitigation professionals serving your area.
PA DEP Certification Requirements for Mitigation Systems
Pennsylvania has required DEP certification for radon mitigation contractors since the Radon Certification Act (Act 43 of 1987) — one of the oldest radon certification programs in the country. The law was a direct response to the Stanley Watras incident in Limerick (1984), when a nuclear plant construction engineer triggered radiation alarms from radon in his Reading Prong home, not from the plant itself.
Why Only DEP-Certified Professionals Can Install ASD Systems
Under Act 43, any person performing radon mitigation services for compensation in Pennsylvania must hold an active PA DEP certification. Certifications are issued and renewed by the PA DEP Bureau of Radiation Protection. There is no grandfather provision — homeowners cannot legally hire unlicensed contractors for mitigation work and have the results recognized for real estate disclosure purposes.
The requirement exists because active sub-slab depressurization (ASD) systems — the dominant mitigation method — must be engineered correctly for the specific foundation type, home size, and sub-slab communication characteristics of each property. An incorrectly sized fan, improperly sealed penetration, or misrouted exhaust can result in elevated radon in living spaces, carbon monoxide backdraft risk, or moisture issues.
Always verify contractor certifications directly through the PA DEP radon contractor database before hiring. Active certification status, not just a license number, is what matters.
The 24-Hour Post-Mitigation Testing Protocol
After an ASD system is installed, a post-mitigation test is required to verify that the system has reduced radon below 4.0 pCi/L. Industry standard and ANSI-AARST guidance calls for a minimum 24-hour closed-house test using a continuous radon monitor (CRM) or charcoal canister placed in the lowest livable area.
If post-mitigation levels remain above 4.0 pCi/L, the system requires adjustment — typically adding suction points, increasing fan capacity, or addressing foundation sealing failures. Reputable DEP-certified contractors include post-mitigation testing in the installation price and guarantee results. Request this guarantee in writing before signing any contract.
For cost guidance on ASD systems across Pennsylvania, see our Pennsylvania radon mitigation cost guide ($843–$2,529 statewide range).
Radon Disclosure in PA Real Estate Transactions
Pennsylvania's residential radon disclosure framework is long-established. The relevant statute — the Real Estate Seller Disclosure Law (68 Pa.C.S. § 7301 et seq.) — has been in effect since 2000 and creates specific obligations for sellers in residential real estate transactions. Understanding what it requires (and what it does not) is critical for both buyers and sellers in high-radon counties.
Interpreting the 4.0 pCi/L EPA Action Level for Home Buyers
The EPA's 4.0 pCi/L action level is the threshold at which mitigation is recommended — not a safety threshold. The EPA has also established a 2.0 pCi/L consideration level at which mitigation is worth evaluating, particularly in high-occupancy homes. The national average indoor radon level is approximately 1.3 pCi/L.
In Pennsylvania, where 40%+ of homes in high-risk counties exceed 4.0 pCi/L, buyers should:
- Insist on a 48-hour short-term CRM test during the inspection contingency period
- Negotiate mitigation costs into the purchase agreement if levels exceed 4.0 pCi/L
- Request post-mitigation test documentation if the seller claims a system is installed
- Verify any listed contractor performed the mitigation holds an active DEP certification
FHA and VA lenders increasingly require radon testing in Zone 1 counties as a condition of financing. Conventional lenders may require it based on appraiser recommendations. Check with your lender early in the transaction if the property is in Berks, Lehigh, Centre, Dauphin, or other high-radon counties. Where the lender orders the test rather than the buyer, the result arrives on a schedule neither party controls — see radon mitigation during a Chester County home sale for how a lender-driven result is handled inside the transaction timeline.
Real Estate Seller Disclosure Law: § 7303 Duty and § 7304(B)(14) Form Contents
Under 68 Pa.C.S. § 7303, sellers must disclose known material defects on the Seller's Property Disclosure Statement (the form itself is governed by § 7304, with radon appearing under § 7304(B)(14)). Required disclosures include:
- Any known radon test results — both pre- and post-mitigation
- The existence of any installed radon mitigation system, including make, model, and installation date if known
- Any known defects in an existing mitigation system
Critical point: the disclosure framework is a disclosure law, not a testing law. Sellers are not required to test — only to disclose results they already have. A seller who has never tested has no obligation to test before listing. This creates a significant information asymmetry in high-radon counties: the most at-risk homes (older construction in Zone 1) are often the least likely to have been tested.
Buyers have no legal mechanism to compel testing under § 7303. Protection comes through the inspection contingency — always include radon testing as a named contingency, not a general inspection clause. The standard PA Association of Realtors contract includes radon contingency language; ensure it is checked and the testing window is specified. When a result comes back at or above 4.0 pCi/L inside that window, the install and the confirming retest both have to fit before settlement — see radon mitigation during a Lancaster County home sale for how that sequence runs. Knowing misrepresentation or omission exposes the seller to statutory damages under § 7311. Pennsylvania homebuyers and sellers navigating radon disclosures should review the PA Home Buyer & Seller Radon Guide, which covers DEP testing protocols, the Real Estate Seller Disclosure Law (68 Pa.C.S. § 7301 et seq.), and mitigation contingency timelines.
To connect with a DEP-certified radon professional in your county, use our free matching service. We connect Pennsylvania property owners with independent, DEP-certified contractors — we do not perform testing or mitigation.
Pennsylvania Radon Compliance: Key Facts
| Standard / Requirement | Detail |
|---|---|
| EPA Action Level | 4.0 pCi/L — mitigation recommended above this threshold |
| EPA Consideration Level | 2.0 pCi/L — evaluate mitigation, especially high-occupancy homes |
| Homeowner Disclosure Law | Real Estate Seller Disclosure Law (68 Pa.C.S. § 7301 et seq.) — duty at § 7303, form contents at § 7304(B)(14), penalties at § 7311 |
| Certification Body | PA Department of Environmental Protection (DEP) Bureau of Radiation Protection |
| Certification Statute | Radon Certification Act — Act 43 of 1987 |
| Primary Mitigation System | Active Sub-Slab Depressurization (ASD) |
| Post-Mitigation Test | Minimum 24-hour closed-house CRM test required |
| Testing Standard (Schools) | ANSI-AARST MA-MFLB protocol |
| Mitigation Standard (Schools) | ANSI-AARST SGM-MFLB standard |
Related Guides
- The Geology of Indoor Radon: Why the Reading Prong and Marcellus Shale Drive Pennsylvania's Radon Crisis →
- Radon in Well Water in Pennsylvania: How Groundwater Adds to Indoor Air Levels →
- Active Sub-Slab Depressurization (ASD): Engineering Standards for Pennsylvania Homeowners →
- Radon Mitigation in Reading, PA: Why Berks County Is the Epicenter of Pennsylvania's Radon Crisis →
- Radon in State College, PA: Pennsylvania's Highest Exceedance Rate at 68.5% →
- Radon Mitigation in Allentown, PA: Dual Geology, 51.2% Exceedance Rate →
Pennsylvania Radon Compliance: City-Level Data
DEP certification obligations apply to mitigation contractors across all Pennsylvania counties. Select your city for local radon risk data, average levels, and DEP-certified contractors. View county-by-county radon risk data in the Pennsylvania County Radon Index.