Yes. An active sub-slab depressurization system, which is what nearly every house in the York area gets, typically cuts radon by 80 to 99 percent. A house testing at 12 pCi/L usually ends up between 0.5 and 2.0. The proof is the post-mitigation test, run a day to a month after the fan is switched on; Pennsylvania DEP certified mitigators are required to tell you to do one. If the follow-up number is still over 4.0, the fix is usually a second suction point or better sealing, not a different kind of system.

In York and York County, a standard system on a house with a basement runs about $875 to $2,200 installed, with most quotes landing between $1,200 and $1,800. Crawl spaces, slabs with no sump, houses that need two suction points, or a fan that has to go through the roof push the number up. The fan then costs about $5 to $10 a month in electricity, and fans last around ten years before they need replacing at $300 to $600. See the cost guide for what a quote should contain.

It is safer than living in one without. A mitigation system does not mean the house is dangerous; it means the house tested high once and someone fixed it. The system pulls the gas from under the slab and vents it above the roof, so indoor levels are usually lower than in a neighbouring house that has never been tested. The only things to check are that the fan is running (the manometer shows uneven liquid levels) and that the house has been re-tested in the last two years.

Legally, a Pennsylvania homeowner may install a system in their own home; the Radon Certification Act only covers people who do the work for pay. Practically, it is a job most people should not take on. The suction point has to be cut and dug under the slab, the pipe has to run to above the roofline, the fan has to be outside the living space, and the joints have to be sealed well enough to actually depressurize the slab. A poorly placed system can run for years while doing nothing. DIY kits and instructions exist; a certified contractor in York County will usually do the whole job for $1,200 to $1,800 and guarantee the result.

Pennsylvania is consistently near the top, along with Iowa, Ohio and the northern Rocky Mountain states. Roughly 40 percent of Pennsylvania homes test above the EPA action level, against a national figure of about one in fifteen. Within the state, the Reading Prong in the Lehigh Valley and Berks County has the most extreme readings, but York, Lancaster, Adams and Cumberland Counties are all EPA Zone 1, and York County has one of the highest shares of homes over 4.0 pCi/L in the state.

Usually January or February. Windows are shut, the furnace is running, and the warm air rising through the house pulls more soil gas in through the foundation. That is why the DEP promotes testing during National Radon Action Month in January: a test then gives you close to a worst-case number. Summer tests tend to read lower, and a real-estate test run with the air conditioning on can understate the annual average.

No law requires it. Pennsylvania has no mandatory testing or mitigation rule for existing homes, and lenders rarely require a test. In practice almost every home sale in York County includes a buyer's radon test because inspectors offer it and the county is Zone 1. The DEP recommends every home be tested, that homes over 4.0 pCi/L be fixed, and that fixed homes be re-tested every two years.

It has to be certified. Under Act 43 of 1987, anyone who tests for or mitigates radon in Pennsylvania for pay must hold a current DEP certification, and testing and mitigation are separate certifications. A handyman, plumber or general contractor without a mitigation certification cannot legally install your system, whatever they say about the work being simple. Ask for the certification number and check it against the DEP Radon Services Directory before you sign anything. Every company listed on this site either prints its DEP certification on its own website or appears on the DEP certified-mitigator or certified-tester list, checked when the listing was added.

The buyer will normally ask you to install a mitigation system before closing, or to credit them the cost. Most York County agreements of sale give the buyer a radon contingency, and a system installed by a certified mitigator with a passing post-test satisfies almost everyone. Expect $1,200 to $1,800 and a week or two of lead time. Pennsylvania's seller disclosure law also requires you to disclose the test result and any system to future buyers, so keep the paperwork.

Very little. Glance at the manometer, the U-shaped tube on the pipe, every month or so: uneven liquid levels mean the fan is pulling, level ones mean it has stopped. Re-test the house every two years and after any major renovation, foundation work or a new HVAC system. The fan itself is the only wearing part; expect to replace it after about ten years. There are no filters to change and nothing to lubricate.

Yes, and treat the system as a plus. It means the house was tested, fixed and probably re-tested, which is more than most houses in York County can say. Have your inspector run a radon test anyway to confirm the system works, check that the manometer shows the fan is pulling, and ask the seller for the installation paperwork and the last post-mitigation test. A working system does not hurt resale; an unmitigated high reading found by the next buyer does.