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National Drinking Water Database


Radon in Maryland


Radon is a radioactive breakdown product of radium and uranium in soil, rock and water; it is often present in groundwater. [read more]

The Most Polluted Communities in Maryland

29 water utilities reported detecting Radon in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Radon level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Pleasant Valley
Westminster, MD
1631 of 110430 pCi/L
(10430 pCi/L)
2Concord Estates Mobile Home Park
Waldorf, MD
1501 of 18568 pCi/L
(8568 pCi/L)
3Town of Hampstead
Hampstead, MD
6,0623 of 32816.67 pCi/L
(2320 to 3580 pCi/L)
4Town of Manchester
Manchester, MD
4,0002 of 22454 pCi/L
(1975 to 2933 pCi/L)
5City of Westminster
Westminster, MD
33,2783 of 32445.83 pCi/L
(1375 to 4450 pCi/L)
6Town of Mount Airy
Mount Airy, MD
8,6311 of 12385 pCi/L
(2385 pCi/L)
7Campus Hills Water Works
Baltimore, MD
2501 of 11562 pCi/L
(1562 pCi/L)
8Woodstock Job Corps Center
Woodstock, MD
6752 of 21558 pCi/L
(1175 to 1941 pCi/L)
9City of Taneytown
Taneytown, MD
6,7502 of 21417.5 pCi/L
(1300 to 1535 pCi/L)
10Town of Poolesville
Poolesville, MD
5,1004 of 41282.5 pCi/L
(850 to 1930 pCi/L)

Health Based Limits for Radon

StandardDescriptionLevel
One in one million (10-6) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 1,000,000. Source: U.S. Environmental Protection Agency.1.5 pCi/L
One in ten thousand (10-4) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 10,000. Source: U.S. Environmental Protection Agency.150 pCi/L

Violation Summary for Radon in Maryland

There are no violations reported for this contaminant in Maryland