--- title: Pennsylvania Building Code and Radon canonical: "https://radonmitigationyorkpa.net/radon-guide/pa-building-code-radon-requirements/" pubDate: "2026-10-01T00:00:00.000Z" updatedDate: "2026-10-03T00:18:00.000Z" author: Radon Mitigation York PA description: "Does Pennsylvania's building code require radon systems in new homes? What the UCC says, where local rules differ and what builders do anyway." --- # Pennsylvania Building Code and Radon Pennsylvania's Uniform Construction Code does not require [radon-resistant construction in new homes](/services/new-construction-radon/) statewide. Radon control methods sit in an appendix to the International Residential Code, and appendices apply only where adopted. Some Pennsylvania municipalities have adopted that appendix locally, so check with your code official before you build. The 2021 code update, in effect since January 1, 2026, did not change this. Under [34 Pa. Code 403.21](https://www.pacodeandbulletin.gov/Display/pacode?file=/secure/pacode/data/034/chapter403/s403.21.html), IRC appendices are not part of the UCC unless the rule lists them, and the radon appendix is not listed. Local adoption varies by municipality, so ask your York City or York County code office what applies to your lot. ## How Pennsylvania's building code works Pennsylvania uses one statewide building code, the Uniform Construction Code (UCC). It is based on the International Code Council's model codes, including the International Residential Code (IRC) for one and two family homes and townhouses. The Department of Labor and Industry, with input from a Review and Advisory Council, decides which code editions and sections Pennsylvania adopts. Pennsylvania moved to the 2021 International Codes, effective statewide on January 1, 2026. The City of York began enforcing the 2021 UCC on that date. The update did not add a statewide radon requirement. ## Where radon appears in the model code The IRC covers radon in an appendix, not in the main body of the code. In earlier editions it was Appendix F, "Radon Control Methods." In the 2021 IRC it is Appendix AF. Appendices are optional. A state or local government has to adopt an appendix for it to become a requirement. According to the Pennsylvania Housing Research Center at Penn State, the UCC does not include any requirement for radon features in new construction, and some townships have adopted Appendix F on their own. ## What the radon appendix requires where adopted Where the appendix is in force, it generally calls for: - A gas-permeable layer, such as clean gravel, under the slab - A soil gas retarder, such as polyethylene sheeting, over that layer - Sealing of slab openings, joints and penetrations - A sealed sump lid if a sump pit is present - A vent pipe from below the slab through the roof - Space and power for a future fan Those are the same core features EPA describes in its [radon-resistant construction basics](https://www.epa.gov/radon/radon-resistant-construction-basics-and-techniques). ## What is required in Pennsylvania today Here is what you can count on, separate from building code: - **Certification.** Pennsylvania's Radon Certification Act and 25 Pa. Code Chapter 240 require anyone who tests or mitigates radon for others to be certified by PA DEP. That includes activating a passive system in a new home for a client. - **Seller disclosure.** Pennsylvania's Real Estate Seller Disclosure Law requires sellers of residential property to disclose what they know about radon, including any tests. Sales of never-occupied new construction can be exempt from the disclosure form when the buyer gets a written warranty of at least one year, the home passed code inspection and a certificate of occupancy was issued. So ask your builder directly about any radon testing. - **Local ordinances.** A municipality that adopted the radon appendix can require RRNC features. Ask the local code office during permitting. There is no statewide requirement that a new home be tested for radon before sale. Many buyers still order a test as part of the inspection, and lenders or relocation companies sometimes ask for one. ## Pending legislation Bills to require radon testing in schools and other buildings have been introduced in Pennsylvania. Some would also require radon-resistant construction for new school buildings. House Bill 289, which would require radon testing in public schools, was reported out of a House committee as amended in March 2026 and then laid on the table. Senate Bills 497 and 760 are still in committee. As of this writing, none of these bills is law. ## Why many builders install RRNC anyway Even without a statewide mandate, RRNC is common practice in high-radon areas. York County is in [EPA Radon Zone 1](https://www.epa.gov/radon/epa-map-radon-zones-and-supplemental-information), the highest potential category. Builders here have good reasons to rough it in: - **Lower cost.** EPA notes that building radon control in is typically cheaper than fixing a home after construction. - **Fewer surprises at closing.** A buyer's radon test that comes back high can delay a sale. A passive stack with an attic outlet makes the fix quick. - **Cleaner look.** A retrofit pipe often runs up the outside of the house. RRNC keeps it inside. - **Buyer demand.** Many buyers ask about radon, especially in Zone 1 counties. ## What new homeowners should know Even with RRNC, a new home needs a test after you move in. A passive system lowers radon in some homes but not all. Our guide to [radon in brand-new homes](/radon-guide/radon-in-new-construction-homes/) explains why new homes can test high and when to test. If you are buying new, ask your builder for the radon details in writing: whether there is gravel or a mat, where the stack runs, whether there is an attic outlet, and whether the pipe is labeled. ## Key takeaways - Pennsylvania's UCC does not require radon-resistant construction statewide. - Radon control methods are in an IRC appendix, which applies only where adopted. - Some Pennsylvania municipalities have adopted the radon appendix locally. - PA does require DEP certification for anyone testing or mitigating for others, and seller disclosure of known radon information. - School radon bills have been introduced but are not law. ## Frequently Asked Questions ### Who enforces building code in York? Your municipality's code office or its third-party inspection agency handles permits and inspections under the UCC. ### Can a township require more than the state code? In some cases, yes. Municipalities can adopt certain local amendments, including code appendices, through an ordinance process set by state law. ### Does a passive radon pipe need a permit? Rules vary. Ask your local code office whether RRNC work needs its own permit or is covered under the building permit. ## Get help with radon on your build We rough in, test and activate radon systems for York builders and homeowners. Call [(717) 356-3035](tel:+17173563035) any time for a same-day callback.