Locations and reports
Radon Levels in Montgomery County, Pennsylvania
What this means for you
- Your area: EPA rates Montgomery County Zone 1, the highest of its three radon zones. That is a prediction for the whole county, and homes with elevated levels occur in all three zones.
- Local tests: Of 10,508 radon tests reported to CDC for Montgomery County (2020), 21.8% were at or above 4 pCi/L, EPA's action level.
- Your home: The only way to know your home’s level is to test it.
pCi/L (picocuries per liter) is the unit radon is measured in. EPA recommends fixing a home at 4 pCi/L or above, its action level.
In 2020, 21.8% of the radon tests reported to CDC for Montgomery County, Pennsylvania came back at or above the EPA action level of 4 pCi/L, and the median result was 2.0 pCi/L. EPA's Map of Radon Zones places the county in Zone 1, highest predicted potential. Radon levels vary from home to home, so only a test measures the level in yours.
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county as a whole.
This is a county-level geologic prediction. It is not a measurement of any address, and houses with elevated radon are found in all three zones.
USGS geologic potential: Low across 100% of the county's land area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Montgomery County, 2020
- Tests reported
- 10,508
- At or above 4 pCi/L
- 21.8%
- Median result
- 2.0 pCi/L
Of 10,508 pre-mitigation tests reported to CDC, not homes in this area. CDC publishes the share in each band, not a count per band, so the per-band counts in the table are calculated by Radon411 and rounded to add up to the published total.
| Result band | Tests Calculated by Radon411 | Share Measured |
|---|---|---|
| Under 2 pCi/L | 5,117 | 48.7% |
| 2 to 4 pCi/L | 3,100 | 29.5% |
| 4 pCi/L and above | 2,291 | 21.8% |
Distribution of tested buildings, not this house. People testing before a sale, or because they suspect a problem, are over-represented in any reported testing data.
Measured: CDC tracking data. Figure above: 2020. Measured data period: 2005 to 2020 (every CDC figure on file).
Montgomery County, In figures
Montgomery County in figures
What the published data says about Montgomery County, in words. A zone and a share of tests describe an area, never the level in any one home.
Predicted
PredictedEPA places Montgomery County in Zone 1, highest predicted potential, as it does 48 other counties of Pennsylvania's 67.
Of the 6 bordering counties, EPA places Berks County, Bucks County, Chester County, Delaware County and Lehigh County in Zone 1 and Philadelphia County in Zone 3.
Reported tests
MeasuredCDC has annual figures for Montgomery County for 7 years, 2014 to 2020. In 2020, 21.8% of 10,508 reported tests were at or above 4 pCi/L.
Across those years the share ranged from 21.8% (2020) to 26.5% (2015). Few tests in a year can move it a long way.
Local record
Pennsylvania's radon program is the Radon Division, run by Department of Environmental Protection; its contacts are under Local resources.
The county's largest incorporated places are Norristown, Pottstown and Lansdale; the figures here cover them as part of the county.
Montgomery County, Reported testing
Reported testing over time
Measured| Year | Median reported result | Highest reported result | Share of tests at or above 4 pCi/L |
|---|---|---|---|
| 2014 | 2.3 pCi/L | 145.3 pCi/L | 26.2% |
| 2015 | 2.3 pCi/L | 303.0 pCi/L | 26.5% |
| 2016 | 2.2 pCi/L | 180.6 pCi/L | 24.8% |
| 2017 | 2.3 pCi/L | 769.7 pCi/L | 25.7% |
| 2018 | 2.1 pCi/L | 281.7 pCi/L | 23.0% |
| 2019 | 2.1 pCi/L | 78.8 pCi/L | 22.1% |
| 2020 | 2.0 pCi/L | 204.9 pCi/L | 21.8% |
What these figures count
Every percentage here is a share of radon tests reported to CDC for Montgomery County in 2020. It is not a share of homes in Montgomery County, and it is not a random sample: it counts only the tests people chose to run and that were reported.
The shares and the median are calculated from pre-mitigation tests (10,508 for 2020). CDC also reports the number of buildings tested (6,972), a different count, so the two totals are not interchangeable.
Montgomery County, State data
Pennsylvania's own radon test data
MeasuredWhat Pennsylvania's own agencies publish about radon tests in Montgomery County, with their period. These are not CDC's figures and are never added to them.
What Pennsylvania DEP reports for the ZIP codes in Montgomery County
Pennsylvania DEP publishes its figures by ZIP code, not by county. These are the 71 ZIP codes that lie wholly or partly in Montgomery County, each with the state's own figures for it. Period: Period not stated by DEP.
| ZIP code | What the state reports |
|---|---|
| 18041 | Basement: average 4.8 pCi/L, 647 tests; First floor: average 2.7 pCi/L, 126 tests |
| 18054 | Basement: average 4.7 pCi/L, 635 tests; First floor: average 2.7 pCi/L, 111 tests |
| 18070 | Basement: average 8.8 pCi/L, 114 tests; First floor: figures not shown |
| 18073 | Basement: average 4.5 pCi/L, 1,575 tests; First floor: average 2.2 pCi/L, 202 tests |
| 18074 | Basement: average 3.7 pCi/L, 982 tests; First floor: average 2.0 pCi/L, 156 tests |
| 18076 | Basement: average 3.4 pCi/L, 357 tests; First floor: average 1.8 pCi/L, 55 tests |
| 18914 | Basement: average 5.3 pCi/L, 6,254 tests; First floor: average 2.9 pCi/L, 1,201 tests |
| 18915 | Basement: average 3.1 pCi/L, 251 tests; First floor: average 2.1 pCi/L, 35 tests |
| 18936 | Basement: average 3.3 pCi/L, 318 tests; First floor: average 1.7 pCi/L, 101 tests |
| 18964 | Basement: average 3.7 pCi/L, 2,395 tests; First floor: average 1.8 pCi/L, 453 tests |
| 18969 | Basement: average 3.8 pCi/L, 2,572 tests; First floor: average 2.1 pCi/L, 543 tests |
| 19001 | Basement: average 3.3 pCi/L, 3,855 tests; First floor: average 2.1 pCi/L, 1,231 tests |
| 19002 | Basement: average 4.3 pCi/L, 9,243 tests; First floor: average 2.6 pCi/L, 1,954 tests |
| 19003 | Basement: average 2.5 pCi/L, 3,078 tests; First floor: average 1.3 pCi/L, 723 tests |
| 19004 | Basement: average 4.0 pCi/L, 3,050 tests; First floor: average 2.0 pCi/L, 596 tests |
| 19006 | Basement: average 4.4 pCi/L, 5,146 tests; First floor: average 2.5 pCi/L, 1,211 tests |
| 19009 | Basement: average 7.2 pCi/L, 129 tests; First floor: average 3.7 pCi/L, 41 tests |
| 19010 | Basement: average 3.2 pCi/L, 4,858 tests; First floor: average 1.7 pCi/L, 1,151 tests |
| 19012 | Basement: average 3.3 pCi/L, 1,794 tests; First floor: average 2.4 pCi/L, 442 tests |
| 19025 | Basement: average 3.7 pCi/L, 1,780 tests; First floor: average 1.9 pCi/L, 409 tests |
| 19027 | Basement: average 4.5 pCi/L, 3,409 tests; First floor: average 2.2 pCi/L, 794 tests |
| 19031 | Basement: average 4.7 pCi/L, 1,395 tests; First floor: average 2.5 pCi/L, 321 tests |
| 19034 | Basement: average 3.9 pCi/L, 1,897 tests; First floor: average 2.5 pCi/L, 465 tests |
| 19035 | Basement: average 4.5 pCi/L, 1,593 tests; First floor: average 3.2 pCi/L, 329 tests |
| 19038 | Basement: average 4.1 pCi/L, 6,178 tests; First floor: average 2.4 pCi/L, 1,422 tests |
| 19040 | Basement: average 3.4 pCi/L, 3,463 tests; First floor: average 1.9 pCi/L, 808 tests |
| 19041 | Basement: average 3.9 pCi/L, 1,595 tests; First floor: average 1.9 pCi/L, 348 tests |
| 19044 | Basement: average 4.3 pCi/L, 3,019 tests; First floor: average 2.2 pCi/L, 1,057 tests |
| 19046 | Basement: average 5.4 pCi/L, 4,404 tests; First floor: average 3.4 pCi/L, 938 tests |
| 19066 | Basement: average 3.9 pCi/L, 1,983 tests; First floor: average 1.8 pCi/L, 401 tests |
| 19072 | Basement: average 4.4 pCi/L, 3,187 tests; First floor: average 2.5 pCi/L, 685 tests |
| 19075 | Basement: average 4.0 pCi/L, 2,212 tests; First floor: average 2.4 pCi/L, 566 tests |
| 19083 | Basement: average 3.0 pCi/L, 8,162 tests; First floor: average 1.8 pCi/L, 1,294 tests |
| 19085 | Basement: average 2.4 pCi/L, 1,955 tests; First floor: average 1.4 pCi/L, 464 tests |
| 19087 | Basement: average 5.7 pCi/L, 12,385 tests; First floor: average 3.6 pCi/L, 2,801 tests |
| 19090 | Basement: average 2.4 pCi/L, 3,062 tests; First floor: average 1.5 pCi/L, 934 tests |
| 19095 | Basement: average 5.6 pCi/L, 1,423 tests; First floor: average 3.3 pCi/L, 340 tests |
| 19096 | Basement: average 3.1 pCi/L, 4,474 tests; First floor: average 1.9 pCi/L, 960 tests |
| 19118 | Basement: average 4.5 pCi/L, 2,852 tests; First floor: average 2.4 pCi/L, 854 tests |
| 19128 | Basement: average 3.2 pCi/L, 6,261 tests; First floor: average 2.1 pCi/L, 1,180 tests |
| 19401 | Basement: average 2.9 pCi/L, 4,852 tests; First floor: average 1.8 pCi/L, 1,262 tests |
| 19403 | Basement: average 4.5 pCi/L, 10,231 tests; First floor: average 2.5 pCi/L, 2,092 tests |
| 19405 | Basement: average 3.0 pCi/L, 722 tests; First floor: average 1.9 pCi/L, 112 tests |
| 19406 | Basement: average 4.4 pCi/L, 4,378 tests; First floor: average 3.8 pCi/L, 946 tests |
| 19422 | Basement: average 3.9 pCi/L, 6,232 tests; First floor: average 2.1 pCi/L, 1,610 tests |
| 19426 | Basement: average 4.2 pCi/L, 12,309 tests; First floor: average 2.5 pCi/L, 1,783 tests |
| 19428 | Basement: average 3.5 pCi/L, 3,917 tests; First floor: average 2.3 pCi/L, 800 tests |
| 19435 | Basement: average 4.9 pCi/L, 36 tests; First floor: figures not shown |
| 19436 | Basement: average 5.4 pCi/L, 82 tests; First floor: figures not shown |
| 19437 | Basement: average 5.3 pCi/L, 448 tests; First floor: average 2.3 pCi/L, 102 tests |
| 19438 | Basement: average 3.8 pCi/L, 5,671 tests; First floor: average 2.3 pCi/L, 1,107 tests |
| 19440 | Basement: average 3.4 pCi/L, 3,158 tests; First floor: average 1.6 pCi/L, 802 tests |
| 19444 | Basement: average 3.8 pCi/L, 3,057 tests; First floor: average 2.6 pCi/L, 833 tests |
| 19446 | Basement: average 4.1 pCi/L, 13,140 tests; First floor: average 2.0 pCi/L, 3,243 tests |
| 19453 | Basement: average 9.4 pCi/L, 165 tests; First floor: figures not shown |
| 19454 | Basement: average 3.7 pCi/L, 6,636 tests; First floor: average 1.9 pCi/L, 1,767 tests |
| 19456 | Basement: average 4.8 pCi/L, 166 tests; First floor: average 2.6 pCi/L, 41 tests |
| 19460 | Basement: average 4.7 pCi/L, 12,115 tests; First floor: average 2.5 pCi/L, 1,760 tests |
| 19462 | Basement: average 4.0 pCi/L, 2,156 tests; First floor: average 2.4 pCi/L, 589 tests |
| 19464 | Basement: average 4.0 pCi/L, 8,254 tests; First floor: average 2.2 pCi/L, 1,063 tests |
| 19468 | Basement: average 4.3 pCi/L, 6,399 tests; First floor: average 2.7 pCi/L, 859 tests |
| 19472 | Basement: figures not shown; First floor: figures not shown |
| 19473 | Basement: average 3.6 pCi/L, 3,542 tests; First floor: average 2.2 pCi/L, 530 tests |
| 19474 | Basement: average 3.0 pCi/L, 522 tests; First floor: average 1.3 pCi/L, 148 tests |
| 19477 | Basement: average 4.3 pCi/L, 132 tests; First floor: average 1.5 pCi/L, 44 tests |
| 19490 | Basement: average 5.4 pCi/L, 340 tests; First floor: average 2.7 pCi/L, 93 tests |
| 19492 | Basement: average 7.8 pCi/L, 127 tests; First floor: figures not shown |
| 19504 | Basement: average 10.7 pCi/L, 1,036 tests; First floor: average 7.9 pCi/L, 133 tests |
| 19505 | Basement: average 8.2 pCi/L, 497 tests; First floor: average 4.5 pCi/L, 40 tests |
| 19512 | Basement: average 10.6 pCi/L, 2,668 tests; First floor: average 6.6 pCi/L, 238 tests |
| 19525 | Basement: average 4.1 pCi/L, 3,305 tests; First floor: average 2.4 pCi/L, 247 tests |
- DEP's report gives the number of tests, the highest result and the average result for each floor tested; it states no period.
- DEP says the smartest thing to do is to test your home for radon, no matter where you live.
- A ZIP code that crosses the county line is listed whole; its figures cover all of it.
Measured: Pennsylvania DEP data, Period not stated by DEP.
Montgomery County, Comparison
How Montgomery County compares
MeasuredMontgomery County's own published CDC figures beside those of the counties that border it, for the same period.
Share of reported tests at or above 4 pCi/L
Measured2020, highest first. Each county’s own published CDC figure.
- Lehigh CountyPA3,103 tests39.8%
- Berks CountyPA2,632 tests39.6%
- Chester CountyPA6,770 tests24.0%
- Bucks CountyPA7,066 tests23.2%
- Montgomery CountyThis page10,508 tests21.8%
- Delaware CountyPA6,041 tests14.7%
- Philadelphia CountyPA8,442 tests10.6%
Median reported result
Measured2020, highest first. Each county’s own published CDC figure.
- Berks CountyPA2,632 tests2.9 pCi/L
- Lehigh CountyPA3,103 tests2.7 pCi/L
- Bucks CountyPA7,066 tests2.0 pCi/L
- Chester CountyPA6,770 tests2.0 pCi/L
- Montgomery CountyThis page10,508 tests2.0 pCi/L
- Delaware CountyPA6,041 tests1.8 pCi/L
- Philadelphia CountyPA8,442 tests1.7 pCi/L
Each figure is that county’s own published CDC figure for 2020, counting radon tests reported to CDC, not homes. Montgomery County is this page. Nothing is averaged or combined across counties. The test count beside each county is CDC’s published number of pre-mitigation tests behind its figures. Figures from few tests can swing widely from year to year. Every Pennsylvania county’s own figure is in the Pennsylvania county table.
CDC publishes this figure only for counties here, so there is no state or national number to compare Montgomery County, Pennsylvania with.
Montgomery County, Bordering counties
Counties bordering Montgomery County
Calculated by Radon4116 counties share a boundary with Montgomery County, computed from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county’s report can be worth reading alongside this one.
- Bucks CountyPAZone 1: Highest predicted potential
- Philadelphia CountyPAZone 3: Lower predicted potential
- Delaware CountyPAZone 1: Highest predicted potential
- Chester CountyPAZone 1: Highest predicted potential
- Lehigh CountyPAZone 1: Highest predicted potential
- Berks CountyPAZone 1: Highest predicted potential
Montgomery County, Local resources
Local resources in Pennsylvania
Who to ask in Pennsylvania: the state's radon program, test kits and professionals.
Radon Division
Department of Environmental Protection
Pennsylvania’s radon program answers questions about testing, mitigation and the rules where you live.
- Phone
- 800-237-2366
- Licensing of radon professionals
The Radon Certification Act requires DEP to establish by regulation, a certification program for persons conducting radon gas and radon progeny testing, laboratory analysis and mitigation...
Test kits
The program says: Through an EPA-funded program, hospitals give parents of newborn children a packet of information which includes a coupon for a free radon test kit from the DEP.
Radon professionals
755 professionals are listed in Pennsylvania.
Professionals in PennsylvaniaMontgomery County, Cities and towns
Cities and towns in Montgomery County
The radon figures on this page are for Montgomery County as a whole. They do not differ by city or town.
- Norristown
- Pottstown
- Lansdale
- Conshohocken
- Hatboro
- Souderton
- Ambler
- Bridgeport
- Collegeville
- Telford (part)
- Royersford
- Jenkintown
- Narberth
- Trappe
- Pennsburg
- Hatfield
- North Wales
- East Greenville
- Rockledge
- Red Hill
- West Conshohocken
- Bryn Athyn
- Schwenksville
- Green Lane
24 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county.
Montgomery County, Questions
Questions about radon in Montgomery County
Common questions8 questions, answered from the figures above
Are radon levels high in Montgomery County?
In 2020, 21.8% of the radon tests reported to CDC for Montgomery County, Pennsylvania were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.0 pCi/L. That is a share of reported tests, not of homes. EPA places Montgomery County in Zone 1, highest predicted potential, a predicted average indoor screening level greater than 4 pCi/L. Homes with elevated levels occur in all three zones, so the figures describe the area, not your house. Testing is the only way to know the radon level in a specific building.
How do I get a radon test in Montgomery County?
EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. No certified tester listed on Radon411 names Montgomery County as a service area yet. The Pennsylvania radon program is the place to ask about certified testers and any test kit offer it runs.
How to test a homeTest kits comparedFree and low-cost kits by statePennsylvania radon program
Who does radon mitigation in Montgomery County?
No listed mitigator names Montgomery County as a service area yet; the Pennsylvania directory lists 755 companies. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional. Your state radon program is the place to check whether Pennsylvania requires one.
How radon mitigation worksWhat mitigation costsMitigators in Pennsylvania
What EPA radon zone is Montgomery County in?
EPA places Montgomery County, Pennsylvania in Zone 1, which EPA describes as highest predicted potential for the area. A zone is a prediction for the whole county and never determines whether a particular home should be tested. EPA recommends testing every home regardless of zone.
Should I test my home in Montgomery County?
Yes. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. How to test a home.
When is the best time of year to test?
EPA says short-term tests stay in the home from 2 to 90 days and that all radon tests should run a minimum of 48 hours; long-term tests stay more than 90 days. EPA's guides do not name a best season: they say radon levels tend to vary from day to day and season to season, so a long-term test is more likely than a short-term test to tell you the year-round average.
What does it cost to test?
EPA's Citizen's Guide calls testing easy and inexpensive, and EPA's Home Buyer's and Seller's Guide says passive short-term and long-term devices are generally inexpensive, while active devices may cost more. No national average price is published for this, so Radon411 does not give one. What testing costs.
Which counties border Montgomery County?
Montgomery County borders 6 counties, derived from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county's report can be relevant.
What these figures mean if you own, buy, sell or rent
The reported-test figures on this page describe Montgomery County, Pennsylvania in 2020. They describe tests other people carried out in other buildings, and none of them measures yours.
- How to test a home
If you own your home
Test the lowest lived-in level; a short-term kit screens in days, a long-term kit reflects the year.
- Buying a house: radon guide
If you are buying
Ask for past results and any system's post-mitigation test, and test during the sale.
- Selling a house: radon guide
If you are selling
Testing before you list puts the timing in your hands; disclosure rules differ by state.
- Radon in rental homes
If you rent, or rent out a home
A tenant can test; a fix is the owner's to make, and duties differ by state.
How long a test has to run, under what conditions, and what EPA says a result means: the testing standard, in full.
Montgomery County, Products
Testing and mitigation products
Whatever the figures for Montgomery County show, only a test tells you about one home.
Testing
- Short-term test kitsPassive detectors exposed for a few days under closed-building conditions, then analyzed by a lab.
- Long-term test kitsDetectors exposed for more than 90 days, for a closer picture of the annual average.
- Continuous monitorsPowered devices that log radon on a repeating cycle, often used for transaction tests.
- Digital detectorsConsumer devices that display a running radon reading without a lab.
- Water radon testsKits for radon dissolved in well water, analyzed by a lab.
Mitigation
- Mitigation fansThe inline fan that keeps a soil depressurization system running, sized by the installer.
- System indicatorsU-tube manometers and fan alarms that show whether a mitigation system is still working.
- Sealing materialsCrack, joint and sump sealing used alongside a mitigation system, not instead of one.
Montgomery County / Next steps
What to do next
Learn
Know what radon is
What radon is, how it gets indoors, and why a county zone is not a reading for your home.
Learn about radonTest
Test the building you live in
Short-term or long-term, where the device goes, and closed-house conditions.
How to testFix
Bring a high level down
How a mitigation system works, and the retest that confirms it.
How mitigation worksFind a pro
Hire a certified professional
Measurement and mitigation professionals by state, with their certifications.
Find a professional
Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.