Skip to content
RADON411

Locations and reports

Radon Levels in Anne Arundel County, Maryland

EPA puts Anne Arundel County in Zone 2, its middle radon zone, and 17.4% of its 4,088 reported radon tests (2008 to 2017, laboratory totals) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    17.4%

    6.5 pts below MD

    Anne Arundel
    17.4%
    Maryland
    23.9%

    4,088 tests, 2008 to 2017

  • Median result

    1.4pCi/L

    Below action level

    Anne Arundel
    1.4 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    4,088

    5th of 19 by tests

    Anne Arundel
    4,088
    Montgomery
    10,969

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Maryland

    16 of 19

    Lowest quarter

    Anne Arundel
    17.4%
    Washington
    56.0%

    By share, of 19 with 30+ tests

Read a result for Anne Arundel County

Starts at Anne Arundel County's median, 1.4 pCi/L

1.4pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 1.4 pCi/L

Below 2 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Anne Arundel County's median reported result, 2008 to 2017.

Interpret this reading

The data

Anne Arundel County, At a glance

Anne Arundel County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Anne Arundel County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 57% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Anne Arundel County, 2008 to 2017, laboratory

Reported results by concentration band, Anne Arundel County, 2008 to 2017, laboratory
Under 2 pCi/L: 64%2 to 4 pCi/L: 19%4 pCi/L and above: 17%

Of 4,088 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Anne Arundel County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L2,60863.8%
2 to 4 pCi/L76818.8%
4 pCi/L and above71217.4%
What these figures count

These are the 4,088 tests reported to CDC for Anne Arundel County over 2008 to 2017 (laboratory totals), many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.

Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Anne Arundel County, Compared

Anne Arundel County radon figures, compared

Calculated by Radon411

Anne Arundel County's 4,088 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.4 pCi/L and a maximum of 294.8 pCi/L, and 17.4% reached 4 pCi/L. Maryland as a whole (24 Maryland counties, pooled) comes to 23.9%: 6.5 points higher than here.

Among its state's counties it ranks 16th of 19 Maryland counties with 30 or more tests for the same period. Statewide for the same period, Washington County reported the highest share (56.0%) and Wicomico County the lowest (0.0%).

Below the action level, 2,608 tests (63.8%) came in under 2 pCi/L, against 56.6% statewide, and 768 tests (18.8%) fell between 2 and 4, against 19.5% statewide. CDC's ten-year totals for Anne Arundel County went from 2,408 tests (2005 to 2014) to 4,088 (2008 to 2017), the share going from 19.4% to 17.4%.

EPA's 1993 zone map puts Anne Arundel County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 57% of the county's land moderate radon potential.

Next door, the shares run from 7.9% in Baltimore city to 30.8% in Howard County, with Baltimore city below Anne Arundel County.

CDC also counts 215 tests taken after mitigation in Anne Arundel County for the same period: tests in homes where a fix was already in.

Anne Arundel County against Maryland, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Anne Arundel County
Anne Arundel County4,08817.4%1.4 pCi/LThis county
Maryland, pooled24 counties, pooled47,94123.9%Not pooled+6.5 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+18.3 points
Washington Countyhighest in the state1,25956.0%5.2 pCi/L+38.6 points
Wicomico Countylowest in the state320.0%0.9 pCi/L−17.4 points
Howard County, MDborders it4,54930.8%2.0 pCi/L+13.4 points
Calvert County, MDborders it1,20530.2%2.0 pCi/L+12.8 points
Baltimore County, MDborders it7,70619.1%1.4 pCi/L+1.7 points
Prince George's County, MDborders it1,60319.0%1.4 pCi/L+1.6 points
Baltimore city, MDborders it1,1487.9%0.8 pCi/L−9.5 points
Where Anne Arundel County's reported results fell, 2008 to 2017, laboratory, beside Maryland and the United States
ResultAnne Arundel County testsAnne Arundel County shareMaryland shareU.S. shareAgainst Maryland
Under 2 pCi/L2,60863.8%56.6%39.6%+7.2 points
2 to 4 pCi/L76818.8%19.5%24.7%−0.7 points
4 pCi/L and above71217.4%23.9%35.7%−6.5 points
Anne Arundel County ranked among the 19 Maryland counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Cecil County9 of 191,07124.9%1.9 pCi/L
Charles County10 of 1947724.1%1.8 pCi/L
Harford County11 of 195,28322.6%1.7 pCi/L
St. Mary's County12 of 1963620.9%1.8 pCi/L
Baltimore County13 of 197,70619.1%1.4 pCi/L
Prince George's County14 of 191,60319.0%1.4 pCi/L
Montgomery County15 of 1910,96918.0%1.3 pCi/L
Anne Arundel County16 of 194,08817.4%1.4 pCi/L
Queen Anne's County17 of 196516.9%1.3 pCi/L
Baltimore city18 of 191,1487.9%0.8 pCi/L
Wicomico County19 of 19320.0%0.9 pCi/L
Anne Arundel County ten-year laboratory totals, against Maryland's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestMaryland, pooledChange from the row before
2008 to 20174,08817.4%1.4 pCi/L294.8 pCi/L23.9%−1.2 points
2007 to 20163,45718.6%1.4 pCi/L294.8 pCi/L24.4%−0.2 points
2006 to 20152,84418.8%1.4 pCi/L294.8 pCi/L24.9%−0.6 points
2005 to 20142,40819.4%1.4 pCi/L294.8 pCi/L24.6%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Anne Arundel County, Geology

The ground under Anne Arundel County

Predicted

USGS's geologic map splits Anne Arundel County: 56.8% of its land is moderate radon potential and 34.1% high. The map puts 56.8% of Anne Arundel County in the area it calls Western Shore and 34.1% in Western Shore. USGS gives the first a radon index of 10, in the moderate band (9 to 11), and the second 12, in the high band (12 to 17).

USGS's geologic areas under Anne Arundel County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Western ShoreCretaceous, Quaternary, minor Tertiary gravel, sand, silt, clay.Moderate1056.8%
Western ShoreTertiary gravel, sand, silt, clay.High1234.1%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Anne Arundel County beside the ground around it

On high-potential ground Anne Arundel County is close to Maryland as a whole: 34.1% of its land against 36.7%. Every one of the 5 counties that border it has more high-potential ground, Howard County the most at 91.2%.

Share of land by USGS radon potential: Anne Arundel County, the 5 counties bordering it and Maryland
AreaEPA zoneLow potentialModerate potentialHigh potential
Anne Arundel CountyZone 2None56.8%34.1%
Prince George's CountyZone 20.1%58.7%38.8%
Baltimore cityZone 2None55.3%36.7%
Howard CountyZone 1None8.8%91.2%
Calvert CountyZone 1NoneNone88.3%
Baltimore CountyZone 1None16.1%81.1%
Maryland24 counties, pooled by land areaVaries29.9%27.6%36.7%

The map rates the ground, not the air in any home.

Local help

Anne Arundel County, Local resources

Radon testing and mitigation in Anne Arundel County

What Maryland's program says
Phone
1-866-703-3266

What it means

Anne Arundel County, Questions

Questions about radon in Anne Arundel County

Are radon levels high in Anne Arundel County?

Over the 2008 to 2017 laboratory totals, 17.4% of the radon tests reported to CDC for Anne Arundel County, Maryland were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.4 pCi/L. Of 19 Maryland counties with 30 or more tests for the same period, 15 reported a higher share; pooled, the state comes to 23.9%.

Which counties border Anne Arundel County?

Anne Arundel County borders 5 counties: Prince George's County, Baltimore city, Howard County, Calvert County and Baltimore County.

Products

Anne Arundel County, Products

Testing a home in Anne Arundel County

In Anne Arundel County, 17.4% of 4,088 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 23.9% pooled across Maryland. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Anne Arundel County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Anne Arundel County homes, compared

Explore

Anne Arundel County, Bordering counties

Counties bordering Anne Arundel County

Calculated by Radon411

Anne Arundel County, Cities and towns

Cities and towns in Anne Arundel County

The Census Bureau estimates 603,380 residents in Anne Arundel County for July 1, 2025, 9,893 more than in 2020 (+1.7%). Packed into its land, that is 1,455 people per square mile. No town dominates: Annapolis, the largest, has 40,634 residents, 6.7% of the total. Together its 2 incorporated places hold 6.8% of those residents; the other 93.2% live outside any of them. CDC's 4,088 reported tests for 2008 to 2017 work out to 6.8 per 1,000 residents (2025 estimate), close to Maryland's 7.7.

From Annapolis to Highland Beach, CDC publishes no figure by town: each reads Anne Arundel County's.

The cities and towns in Anne Arundel County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Annapolis40,634−0.4%6.7%
Highland Beach104−1.9%Under 0.1%

2 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).

Anne Arundel County, Homes

Homes in Anne Arundel County

Of Anne Arundel County's 234,843 homes, 59% are detached houses, against 51% across Maryland; 16% are in buildings of five or more homes. Half of its homes were built before 1983, close to Maryland's 1979: 19% date from before 1960 and 24% from 2000 or later. 75% of occupied homes are lived in by their owner (Maryland: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Anne Arundel County, Maryland, 2019 to 2023
HomesAnne Arundel CountyMaryland
Housing units234,8432,545,532
Detached houses59%51%
In buildings of 5 or more16%23%
Mobile homes1%1%
Built before 196019%27%
Built since 200024%20%
Middle year built19831979
Owner-occupied75%67%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.