---
title: Radon Guide
canonical: "https://radonmitigationyorkpa.net/radon-guide/"
description: "Plain-language radon articles for York, PA: testing, mitigation systems, costs, real estate, older homes, crawl spaces, sump pits and well water."
---

# Radon Guide

Plain-language radon articles for York, PA: testing, mitigation systems, costs, real estate, older homes, crawl spaces, sump pits and well water.

- [Aeration vs. GAC Carbon Filters for Radon in Water](https://radonmitigationyorkpa.net/radon-guide/aeration-vs-carbon-filter-radon-water.md): Aeration or a GAC carbon filter for radon in your well? Compare removal rates, radioactive buildup, upkeep and cost so you pick the right system.
- [Best Radon Mitigation Fan: RadonAway, Fantech and Festa Compared](https://radonmitigationyorkpa.net/radon-guide/best-radon-fan.md): Comparing radon fans from RadonAway, Fantech and Festa. What separates models, how installers match a fan to your soil, and why best depends on your house.
- [The Best Time of Year to Test for Radon](https://radonmitigationyorkpa.net/radon-guide/best-time-to-test-for-radon.md): You can test for radon any time of year. Learn why winter results often run higher, why January is Radon Action Month and how to time your test.
- [Block Wall Basements and Radon](https://radonmitigationyorkpa.net/radon-guide/block-wall-radon-mitigation.md): Hollow concrete block walls carry radon up through their cores. Learn how block-wall depressurization and top-course sealing fix it.
- [Buying a House With a Radon Mitigation System](https://radonmitigationyorkpa.net/radon-guide/buying-a-house-with-a-radon-system.md): A radon system is usually a plus. Here is how to check the fan, the manometer, past test results and the installer before you buy in York, PA.
- [Closed-House Conditions for a Radon Test](https://radonmitigationyorkpa.net/radon-guide/closed-house-conditions-radon-test.md): Closed-house conditions mean windows and outside doors shut 12 hours before and during a short radon test. See what you can and cannot do.
- [Commercial Radon Mitigation Cost](https://radonmitigationyorkpa.net/radon-guide/commercial-radon-mitigation-cost.md): How commercial and multifamily radon mitigation is priced: building size, slab layout, fan count, testing and standards. Get a free written quote.
- [How Commercial and Multifamily Radon Testing Works](https://radonmitigationyorkpa.net/radon-guide/commercial-radon-testing-protocol.md): How commercial and multifamily radon testing differs from a home test: ANSI/AARST MA-MFLB-2023 test locations, HVAC rules, timing and follow-up.
- [Crawl Space Dehumidifiers and Radon](https://radonmitigationyorkpa.net/radon-guide/crawl-space-dehumidifier-and-radon.md): A crawl space dehumidifier controls moisture but does not remove radon. Learn how it pairs with a sealed membrane and radon fan in an encapsulated crawl.
- [Crawl Space Radon Mitigation Cost](https://radonmitigationyorkpa.net/radon-guide/crawl-space-radon-mitigation-cost.md): What crawl space radon mitigation costs, how sub-membrane systems are priced, and how encapsulation changes the total for York homeowners.
- [Do Crawl Space Vents Reduce Radon?](https://radonmitigationyorkpa.net/radon-guide/crawl-space-vents-and-radon.md): Open crawl space vents can dilute radon, but results swing with the weather and bring moisture and frozen-pipe risks. See what works better.
- [Are Digital Radon Monitors Accurate?](https://radonmitigationyorkpa.net/radon-guide/digital-radon-monitor-accuracy.md): Consumer digital radon monitors are good for trends but are not certified test devices. Learn how accurate they are and when you need a certified test.
- [Radon in a Dirt-Floor Basement](https://radonmitigationyorkpa.net/radon-guide/dirt-floor-basement-radon.md): A dirt floor gives radon a wide-open path into your home. Compare a sealed membrane with suction to pouring a new slab, and handling partial dirt floors.
- [DIY Radon Mitigation in Pennsylvania: What the Law Allows and What to Watch For](https://radonmitigationyorkpa.net/radon-guide/diy-radon-mitigation-pa.md): Can you install your own radon system in PA? What the law allows, the steps involved, and why DIY systems often fail the clearance test.
- [Do Air Purifiers Remove Radon?](https://radonmitigationyorkpa.net/radon-guide/do-air-purifiers-remove-radon.md): Air purifiers don't reliably remove radon, and EPA does not recommend them for radon risk. Learn why, and what lowers radon levels.
- [Do Older Homes Have More Radon?](https://radonmitigationyorkpa.net/radon-guide/do-older-homes-have-more-radon.md): Age doesn't cause radon, but old foundations often let more in. Learn why older homes often test higher and why new homes still need a test.
- [Do Radon Mitigation Systems Actually Work?](https://radonmitigationyorkpa.net/radon-guide/do-radon-mitigation-systems-work.md): Yes, radon systems work when installed right. See how much they lower radon, why some fall short, and how to make sure yours keeps working.
- [Does a Radon System Affect Home Value?](https://radonmitigationyorkpa.net/radon-guide/does-a-radon-system-affect-home-value.md): A working radon system generally does not hurt resale value. In a Zone 1 county like York, many buyers expect one. Here is why.
- [Does a Sump Pump Cause Radon?](https://radonmitigationyorkpa.net/radon-guide/does-a-sump-pump-cause-radon.md): A sump pump does not make radon, but an open sump pit lets soil gas pour into your basement. Here is why, and how to close that path for good.
- [Does Crawl Space Encapsulation Reduce Radon?](https://radonmitigationyorkpa.net/radon-guide/does-crawl-space-encapsulation-reduce-radon.md): Encapsulation alone cuts radon only a little. Learn why, and how adding suction under the liner turns an encapsulated crawl space into a radon system.
- [Does Homeowners Insurance Cover Radon Mitigation?](https://radonmitigationyorkpa.net/radon-guide/does-insurance-cover-radon-mitigation.md): Homeowners insurance rarely covers radon mitigation. Learn why, the few exceptions, and who usually pays when a York home is bought or sold.
- [Does Radon Mitigation Reduce Basement Moisture?](https://radonmitigationyorkpa.net/radon-guide/does-radon-mitigation-reduce-basement-moisture.md): A radon system can lower basement humidity a little as a side effect, but it is not waterproofing. Here is what to expect and when you need more help.
- [Does Sealing Cracks Reduce Radon? What Radon Sealant for Concrete Can and Cannot Do](https://radonmitigationyorkpa.net/radon-guide/does-sealing-cracks-reduce-radon.md): Can a radon sealant for concrete fix high radon? What the EPA says about sealing cracks, where sealing helps, and why it works best with a fan system.
- [Using Perimeter Drain Tile for Radon Mitigation](https://radonmitigationyorkpa.net/radon-guide/drain-tile-radon-mitigation.md): How a radon fan uses your drain tile and sump pit as one big suction point, when it works best, and when a separate slab hole is the better choice.
- [Free and Low-Cost Radon Test Kits in Pennsylvania](https://radonmitigationyorkpa.net/radon-guide/free-radon-test-kit-pennsylvania.md): Pennsylvania residents can sometimes get a free radon test kit through PA DEP and the American Lung Association. See current options and low-cost kits.
- [How Does a Radon Mitigation System Work?](https://radonmitigationyorkpa.net/radon-guide/how-does-a-radon-mitigation-system-work.md): A plain-English look at how a radon system pulls soil gas from under your slab and vents it above the roof, part by part, plus how to tell it works.
- [How Long Does a Radon Fan Last?](https://radonmitigationyorkpa.net/radon-guide/how-long-does-a-radon-fan-last.md): Most radon fans run 5 to 10 years. Learn what shortens fan life, the warning signs of failure, and what the 5-year warranties cover.
- [How Long Does a Radon Test Take?](https://radonmitigationyorkpa.net/radon-guide/how-long-does-a-radon-test-take.md): A short-term radon test runs at least 48 hours; a long-term test runs over 90 days. See the full timeline, from closed-house prep to your results.
- [How Long Does Radon Mitigation Take?](https://radonmitigationyorkpa.net/radon-guide/how-long-does-radon-mitigation-take.md): Most radon systems are installed in one day. See the full timeline, from quote to clearance test, and what can make a job run longer.
- [How Does Radon Get Into a House?](https://radonmitigationyorkpa.net/radon-guide/how-radon-enters-a-home.md): Radon enters through foundation cracks, slab joints, sump pits, pipe gaps and crawl space soil. See why homes pull it in and how it is stopped.
- [How to Choose a Radon Mitigation Contractor in Pennsylvania](https://radonmitigationyorkpa.net/radon-guide/how-to-choose-a-radon-contractor.md): Check PA DEP certification, compare written quotes and ask the right questions. A plain-English checklist for hiring a radon contractor in Pennsylvania.
- [How to Tell If Your House Has a Radon Pipe](https://radonmitigationyorkpa.net/radon-guide/how-to-tell-if-house-has-radon-pipe.md): Look for a labeled PVC pipe in the basement, a stack through the attic and an outlet nearby. Here's how to spot a radon pipe in 5 steps.
- [How to Test Well Water for Radon](https://radonmitigationyorkpa.net/radon-guide/how-to-test-well-water-for-radon.md): Radon escapes from water fast, so sampling matters. Learn which tap to use, how to fill the vial with no bubbles and how fast it must reach the lab.
- [Is High Radon a Deal Breaker When Buying a House?](https://radonmitigationyorkpa.net/radon-guide/is-radon-a-deal-breaker.md): High radon rarely kills a home sale. Learn why it is fixable in about a day, how York deals handle it, and when walking away makes sense.
- [Is Radon in Water Dangerous?](https://radonmitigationyorkpa.net/radon-guide/is-radon-in-water-dangerous.md): Most of the risk from radon in well water comes from breathing gas released in showers and laundry, not drinking it. Here is what the data shows.
- [Is Radon Mitigation Tax Deductible?](https://radonmitigationyorkpa.net/radon-guide/is-radon-mitigation-tax-deductible.md): Radon mitigation is generally not tax deductible for a primary home. Learn the narrow exceptions for rentals, cost basis and medical expenses.
- [Is Radon Dangerous, or Is It Overblown?](https://radonmitigationyorkpa.net/radon-guide/is-radon-overblown.md): Is radon a real danger or a sales pitch? We look at the studies, the fair criticisms and what the numbers mean for your home, without the hype.
- [Radon Mitigation for Homes with a Basement and a Crawl Space](https://radonmitigationyorkpa.net/radon-guide/mixed-foundation-radon-mitigation.md): Have a basement and a crawl space? One fan can often treat both. See how the two areas tie together and when a second suction point is needed.
- [January Is National Radon Action Month](https://radonmitigationyorkpa.net/radon-guide/national-radon-action-month.md): January is National Radon Action Month. Learn why EPA picks winter, why it's a smart time to test in York County, and what to do with your result.
- [Can Your Radon Level Differ From Your Neighbor's?](https://radonmitigationyorkpa.net/radon-guide/neighbor-radon-levels.md): A neighbor's low radon test doesn't clear your home. Soil, cracks, foundation type and air flow make every house different. Here's why.
- [NRPP vs. PA DEP Radon Certification](https://radonmitigationyorkpa.net/radon-guide/nrpp-vs-pa-dep-certification.md): Pennsylvania requires PA DEP radon certification to test or mitigate for others. Here is how it differs from NRPP and how to check any contractor.
- [Why Older Homes Cost More to Mitigate](https://radonmitigationyorkpa.net/radon-guide/older-home-radon-mitigation-cost.md): Why radon mitigation costs more in older York homes with stone or block foundations: extra suction points, sealing and pipe routing explained.
- [Pennsylvania Building Code and Radon](https://radonmitigationyorkpa.net/radon-guide/pa-building-code-radon-requirements.md): Does Pennsylvania's building code require radon systems in new homes? What the UCC says, where local rules differ and what builders do anyway.
- [Radon Rules for Pennsylvania Landlords](https://radonmitigationyorkpa.net/radon-guide/pa-landlord-radon-requirements.md): Do PA landlords have to test for radon? What state law says today, where disclosure applies, what lenders may require and best practice for rental owners.
- [Do You Have to Disclose Radon in PA? Pennsylvania Radon Disclosure Rules for Sellers](https://radonmitigationyorkpa.net/radon-guide/pa-radon-disclosure-law.md): Pennsylvania sellers must disclose known radon tests, results and systems. See what the law requires, what it does not, and how to handle it.
- [Pennsylvania Radon Mitigation Standards (25 Pa. Code 240)](https://radonmitigationyorkpa.net/radon-guide/pa-radon-mitigation-standards.md): What Pennsylvania's radon mitigation standards require: exhaust location, fan placement, sealing, labels, gauges and testing, in plain English.
- [Cost to Activate a Passive Radon System](https://radonmitigationyorkpa.net/radon-guide/passive-radon-activation-cost.md): What it costs to add a fan to a passive radon pipe, what the job includes, and how to tell if your York home is radon-ready.
- [Passive vs. Active Radon Systems](https://radonmitigationyorkpa.net/radon-guide/passive-vs-active-radon-system.md): Passive radon systems rely on natural draft; active ones use a fan. Compare how well each works, costs, upkeep, and when to switch.
- [Professional Radon Test vs. Home Test Kit: Which Should You Use?](https://radonmitigationyorkpa.net/radon-guide/professional-radon-test-vs-home-kit.md): Home radon kits and professional tests can both be valid. See how they differ in accuracy, cost and real-estate use, and when you need a certified test.
- [Questions to Ask Your Builder About Radon](https://radonmitigationyorkpa.net/radon-guide/questions-to-ask-builder-about-radon.md): A short checklist for new-home buyers: what radon features to ask about, where the vent stack goes, the attic outlet, testing and who pays to add a fan.
- [How the Radon Contingency Works in a PA Purchase Agreement](https://radonmitigationyorkpa.net/radon-guide/radon-contingency-pennsylvania.md): How radon fits the inspection contingency in a PA agreement of sale: the test window, the buyer's options, the seller's response and deadlines.
- [Radon Credit at Closing vs. Seller-Installed System](https://radonmitigationyorkpa.net/radon-guide/radon-credit-vs-seller-mitigation.md): Should the seller install a radon system or give a credit at closing? Compare control, timing, proof and lender rules before you decide.
- [How Much It Costs to Run a Radon Fan](https://radonmitigationyorkpa.net/radon-guide/radon-fan-electricity-cost.md): How much electricity a radon fan uses and what it costs per month at Pennsylvania rates, with a simple table by fan wattage.
- [Radon Fan Noise: Causes and Fixes](https://radonmitigationyorkpa.net/radon-guide/radon-fan-noise.md): Radon fan humming, rattling or grinding? Learn which noises are normal, what causes the rest, and which fixes don't need a new fan.
- [Radon Fan Not Working: Troubleshooting Guide](https://radonmitigationyorkpa.net/radon-guide/radon-fan-not-working.md): Radon fan stopped or gauge reading zero? Run these safe checks for power, ice and blockages, and learn when the fan needs replacing.
- [Radon Fan Replacement Cost](https://radonmitigationyorkpa.net/radon-guide/radon-fan-replacement-cost.md): How much radon fan replacement costs, what drives the price, signs your fan is failing, and when a repair makes more sense than a new fan.
- [Radon Guide for York Real Estate Agents](https://radonmitigationyorkpa.net/radon-guide/radon-guide-for-real-estate-agents.md): A practical radon guide for York agents: test timing, PA rules, contingency requests, seller disclosure and keeping a high result from delaying closing.
- [Radon Exposure Symptoms and Health Risks](https://radonmitigationyorkpa.net/radon-guide/radon-health-risks.md): Radon causes no immediate symptoms. The main risk, per EPA and CDC, is lung cancer after years of exposure. Here are the facts, without the scare.
- [Radon in Apartments and Multifamily Buildings](https://radonmitigationyorkpa.net/radon-guide/radon-in-apartments.md): Radon in apartments is highest in ground-floor units, but upper floors are not always safe. Which units to test, how to fix it and who is responsible.
- [Can a House Without a Basement Have Radon?](https://radonmitigationyorkpa.net/radon-guide/radon-in-homes-without-basements.md): Slab-on-grade and crawl space homes can test high for radon. See York County test data by floor type and how radon is fixed in homes without basements.
- [Radon in Brand-New Homes](https://radonmitigationyorkpa.net/radon-guide/radon-in-new-construction-homes.md): Yes, brand-new homes can have high radon, even with a passive pipe. Why new houses test high, when to test after move-in and what to do with the result.
- [What Level of Radon in Water Is Too High?](https://radonmitigationyorkpa.net/radon-guide/radon-in-water-levels.md): EPA proposed 300 and 4,000 pCi/L limits for radon in water in 1999 but never finalized them. Here is how to read your well result and decide.
- [Radon in Well Water: A Guide for York County Homeowners](https://radonmitigationyorkpa.net/radon-guide/radon-in-well-water.md): How radon gets into private wells, why York County wells are worth testing, and when water radon is worth treating. Plain-English guide.
- [Radon Levels Before and After Mitigation: What the Data Shows](https://radonmitigationyorkpa.net/radon-guide/radon-levels-before-and-after-mitigation.md): What radon level to expect after mitigation, from EPA, Health Canada and Pennsylvania data: results by method, why the installer matters, and what to aim for.
- [Radon Manometer Reading: What Your U-Tube Gauge Is Telling You](https://radonmitigationyorkpa.net/radon-guide/radon-manometer-reading.md): How to read the U-tube manometer on your radon pipe, what a normal reading looks like, and what it means when the liquid is level or reads zero.
- [Getting Radon Mitigation Done Before Closing](https://radonmitigationyorkpa.net/radon-guide/radon-mitigation-before-closing.md): Yes, radon mitigation can be done before closing. See the install, 24-hour wait and retest timeline, plus the paperwork lenders and agents need.
- [Financial Help for Radon Mitigation in Pennsylvania](https://radonmitigationyorkpa.net/radon-guide/radon-mitigation-financial-help-pa.md): Is there financial help for radon mitigation in Pennsylvania? What programs exist, what to verify, and other ways York homeowners cover the cost.
- [Radon Mitigation in a Finished Basement: How It Is Done](https://radonmitigationyorkpa.net/radon-guide/radon-mitigation-finished-basement.md): Yes, you can fix radon in a finished basement. How installers place the suction point, hide the pipe and protect your walls and floors.
- [Can Radon Mitigation Be Installed in Winter?](https://radonmitigationyorkpa.net/radon-guide/radon-mitigation-in-winter.md): Yes, radon systems can be installed in winter. What changes in cold weather, how installers prevent frozen pipes, and why winter is a smart time to act.
- [Interior vs. Exterior Radon Mitigation Systems: Which Pipe Route Is Right?](https://radonmitigationyorkpa.net/radon-guide/radon-pipe-routing-interior-vs-exterior.md): Should your radon pipe run inside or up the outside wall? Compare cost, looks, noise and winter performance before you choose a route.
- [Radon-Resistant New Construction (RRNC) Explained](https://radonmitigationyorkpa.net/radon-guide/radon-resistant-new-construction.md): The five parts of radon-resistant new construction, how a passive stack works, what it costs compared with a retrofit, and why you still need to test.
- [Retesting After Radon Mitigation: When and How Often](https://radonmitigationyorkpa.net/radon-guide/radon-retest-after-mitigation.md): Test no sooner than 24 hours and within 30 days of mitigation, then every two years. Here is the full retest schedule, plus after repairs.
- [Radon Still High After Mitigation: Why It Happens and How to Fix It](https://radonmitigationyorkpa.net/radon-guide/radon-still-high-after-mitigation.md): Radon still high after a mitigation system went in? Learn the common causes, how installers diagnose them, and what a clearance guarantee should cover.
- [Sealed Sump Pit Covers for Radon](https://radonmitigationyorkpa.net/radon-guide/radon-sump-pit-cover.md): What makes a sump pump radon cover airtight: gaskets, sealed cord and pipe ports, a viewing window and a removable lid. Plus when a cover is not enough.
- [Radon System Alarm Going Off: What to Do](https://radonmitigationyorkpa.net/radon-guide/radon-system-alarm.md): Your radon alarm means suction dropped. Run these quick checks for power, ice and blockages, and learn when the alarm means a new fan.
- [Moving a Radon System During a Basement Remodel](https://radonmitigationyorkpa.net/radon-guide/radon-system-during-remodel.md): Finishing your basement? Learn how to relocate or box in a radon system the right way, what must stay visible, and why you retest after.
- [Radon Systems on Historic Homes](https://radonmitigationyorkpa.net/radon-guide/radon-system-historic-home.md): You can add a radon system to a historic home without spoiling the facade. Pipe routing, fan placement and review steps for older and historic houses.
- [Radon System Maintenance Checklist](https://radonmitigationyorkpa.net/radon-guide/radon-system-maintenance.md): Keep your radon system working with this monthly, seasonal and two-year checklist. Gauge checks, fan checks, sealing and retesting.
- [What a Radon Mitigation System Looks Like Outside a House](https://radonmitigationyorkpa.net/radon-guide/radon-system-on-house-exterior.md): What a radon system looks like on the outside of a house: the pipe, fan and roof vent, the rules for where they go, and ways to make them blend in.
- [Radon System Warranties Explained](https://radonmitigationyorkpa.net/radon-guide/radon-system-warranty.md): What a radon mitigation warranty covers: the fan maker's warranty, the installer's workmanship warranty and a clearance guarantee. Know what to ask for.
- [Radon Test Results Explained: How to Read Your Number](https://radonmitigationyorkpa.net/radon-guide/radon-test-results-explained.md): What does your radon number mean? Learn the 4.0 pCi/L action level, the 2 to 4 gray zone, how to read a monitor report and what to do next.
- [Radon Test Tampering in a Home Sale](https://radonmitigationyorkpa.net/radon-guide/radon-test-tampering-home-sale.md): How radon test tampering happens in a home sale, how PA testing rules and monitors detect it, and what buyers and sellers should do about it.
- [Radon Testing Cost: What You Will Pay in York](https://radonmitigationyorkpa.net/radon-guide/radon-testing-cost.md): What a radon test costs in York, PA: home kits vs. professional tests, what each price includes, and which one you need for a home sale.
- [Radon Testing During a Home Inspection](https://radonmitigationyorkpa.net/radon-guide/radon-testing-during-home-inspection.md): Order the radon test with your home inspection so results land inside the contingency window. Learn timing, rules and how to read the results.
- [Radon Testing in Pennsylvania Schools and Daycares](https://radonmitigationyorkpa.net/radon-guide/radon-testing-schools-and-daycares-pa.md): Are PA schools and daycares required to test for radon? Current law, the status of House Bill 289 and how schools and child care centers can test now.
- [Radon in Water Treatment Cost](https://radonmitigationyorkpa.net/radon-guide/radon-water-treatment-cost.md): What radon in water treatment costs for York-area private wells: aeration vs. carbon filters, running costs, and when treatment makes sense.
- [Radon Mitigation in York Rowhomes and Twins](https://radonmitigationyorkpa.net/radon-guide/rowhome-radon-mitigation.md): Shared walls, tight lots and close neighbors change how a radon system goes into a York rowhome or twin. Pipe routes, testing and neighbors explained.
- [What Radon Level Is Safe?](https://radonmitigationyorkpa.net/radon-guide/safe-radon-levels.md): No radon level is risk-free. EPA says fix at 4.0 pCi/L or higher and consider fixing from 2 to 4. See what your number means and what to do next.
- [Servicing a Sump Pump With a Radon Cover](https://radonmitigationyorkpa.net/radon-guide/servicing-sump-pump-with-radon-cover.md): Yes, you can still reach your sump pump under a radon cover. Step-by-step: shut off the fan, open the lid, service the pump and reseal it the right way.
- [Short-Term vs. Long-Term Radon Tests: Which Do You Need?](https://radonmitigationyorkpa.net/radon-guide/short-term-vs-long-term-radon-test.md): Short-term radon tests give a fast answer in 2 to 90 days. Long-term tests show your true yearly average. Learn which fits a home sale or your own home.
- [Should a Radon Fan Run All the Time?](https://radonmitigationyorkpa.net/radon-guide/should-radon-fan-run-all-the-time.md): Your radon fan should run 24/7. Learn why turning it off lets radon return, what it costs to run, and what to do if it keeps shutting off.
- [Radon Mitigation for Fieldstone Foundations](https://radonmitigationyorkpa.net/radon-guide/stone-foundation-radon-mitigation.md): Fieldstone walls leak soil gas through every joint. See how radon systems handle stone foundations: extra suction, sealing and wall membranes.
- [Sub-Membrane Depressurization (SMD) Explained](https://radonmitigationyorkpa.net/radon-guide/sub-membrane-depressurization.md): How sub-membrane depressurization lowers radon in crawl spaces and dirt floors: the membrane, sealing, suction point, fan and how to tell it works.
- [Sub-Slab Depressurization for Radon, Explained](https://radonmitigationyorkpa.net/radon-guide/sub-slab-depressurization.md): What sub-slab depressurization is, why the EPA favors it for radon, how it is installed in a basement, and what makes it work well or poorly.
- [Vapor Barrier vs. Radon Barrier](https://radonmitigationyorkpa.net/radon-guide/vapor-barrier-vs-radon-barrier.md): A loose vapor barrier is not a radon barrier. Compare thickness, sealing and suction, and learn when an existing crawl space liner can be upgraded.
- [Water or Gurgling in a Radon Pipe: What It Means](https://radonmitigationyorkpa.net/radon-guide/water-in-radon-pipe.md): Water in your radon pipe is usually condensation draining by design. Learn when gurgling is normal and when it means a pipe slope problem.
- [Radon Mitigation in a Wet or Damp Basement](https://radonmitigationyorkpa.net/radon-guide/wet-basement-radon-mitigation.md): A damp or wet basement can still get a working radon system. Learn how sumps, drains, wet soil and high water change the design, and what to fix first.
- [What Is a Passive Radon System?](https://radonmitigationyorkpa.net/radon-guide/what-is-a-passive-radon-system.md): A passive radon system is a builder-installed pipe with no fan. Learn how it works, why many still test high, and when to add a fan.
- [What Does pCi/L Mean for Radon?](https://radonmitigationyorkpa.net/radon-guide/what-is-pci-l.md): pCi/L means picocuries per liter, the unit for radon in air. Learn what the number counts, how it converts to Bq/m3 and what 4.0 pCi/L means.
- [What Is Radon and Where Does It Come From?](https://radonmitigationyorkpa.net/radon-guide/what-is-radon.md): Radon is a colorless, odorless radioactive gas made as uranium in soil and rock breaks down. Learn where it comes from and why homes trap it.
- [Where to Place a Radon Test in Your Home](https://radonmitigationyorkpa.net/radon-guide/where-to-place-a-radon-test.md): Put your radon test in the lowest lived-in level, 20 inches up, away from drafts, walls, sumps and humidity. See the full placement checklist.
- [Who Pays for Radon Mitigation: Buyer or Seller?](https://radonmitigationyorkpa.net/radon-guide/who-pays-for-radon-mitigation.md): In PA, who pays for radon mitigation is negotiated during the inspection contingency. See the common outcomes and how to choose the right one.
- [Why Is Radon So High in York County?](https://radonmitigationyorkpa.net/radon-guide/why-is-radon-high-in-york-county.md): York County's limestone valley and fractured schist hills hold uranium and give radon easy paths into homes. Here is the geology in plain English.
- [Why Radon Mitigation Quotes Vary](https://radonmitigationyorkpa.net/radon-guide/why-radon-mitigation-quotes-vary.md): Why radon mitigation quotes can differ by hundreds of dollars, what each one should include, and how to compare them line by line.
- [Why Two Radon Tests Give Different Results](https://radonmitigationyorkpa.net/radon-guide/why-radon-test-results-vary.md): Two radon tests in the same house can disagree. Learn how weather, season, placement, device error and test length change results, and what to do next.