DIY radon mitigation vs a DEP-certified contractor in Pennsylvania
You may install your own system in Pennsylvania. Whether you should, what usually goes wrong, and how to verify a contractor's certification.
"Radon mitigation DIY" is a real search with real kits behind it, and the honest answer has two halves: it is legal for you to do it in your own house, and it is harder to do well than the kits suggest.
The law
The Radon Certification Act (Act 43 of 1987) requires anyone who tests for, mitigates or provides radon safety services for compensation in Pennsylvania to be certified by the DEP. It does not stop a homeowner working on their own residence. It does mean that the plumber who offers to "run a pipe and stick a fan on it", the handyman, the HVAC company and the general contractor cannot legally do the work unless they hold a mitigation certification, and it means that in a home sale the buyer's side will want a certified installer's paperwork, not a homeowner's.
What a DIY install involves
Coring a four-inch hole through the slab and digging a pit beneath it, or sealing the sump with a proper lid; running PVC through the house or up the outside wall to above the roof eave; mounting an in-line fan in the attic, garage or outdoors with an electrical connection; fitting a manometer; sealing cracks, the floor-wall joint and the sump; and testing afterwards. The parts run $400 to $700.
Where it goes wrong
- Wrong suction point. Without a diagnostic test you do not know whether one point will depressurize the slab. Many DIY systems pull a strong vacuum on one corner and nothing across the rest.
- Fan in the wrong place. Inside the basement or in a first-floor closet, which puts pressurised radon-laden pipe inside the house.
- Pipe ends too low. Below the eave or near a window, the exhaust re-enters the house.
- Pulling conditioned air. An oversized fan on a leaky slab sucks heated basement air out all winter.
- No post-test, so the system runs for years without anyone knowing it does nothing.
What a certified contractor adds
A diagnostic test, the right fan for the soil, a guaranteed result (under 4.0 pCi/L and usually under 2.0), the post-mitigation test, a warranty on the fan, and paperwork a buyer will accept. In York County that is $1,200 to $1,800 all in, against $400 to $700 in parts and a weekend. For most people the difference buys a system that is known to work.
How to check a contractor
- Ask for the DEP certification number. Mitigation and testing are separate; you want the mitigation one for an install.
- Look it up in the DEP Radon Services Directory, filtered to York County, and check it is current.
- Ask for proof of liability insurance.
- Ask what the post-test target is and who runs it.
Every company in this directory either prints its DEP certification on its own website or was on the DEP list when it was added. Certifications lapse; check the number yourself before you sign.
Last updated 2026-09-28. General information for the York area, not professional advice; confirm specifics with a qualified contractor or your insurer.