Government sampling of groundwater in Baltimore County's 400BLMR aquifer shows radon-222 was detected in all tested wells, with levels ranging from 227 to 4900 picocuries per liter (pCi/L) and a median of 3470 pCi/L. These figures come from three wells sampled between February 2019 and January 2020, each well 200 to 300 feet deep. No measurement in this set exceeded federal thresholds.
How Public-System Records Differ from Private-Well Testing
Government sampling covers multiple wells in an area, not individual homes
US Geological Survey data reflects radon concentrations from a limited number of wells representing the 400BLMR aquifer. These measurements provide area-wide context but cannot specify the radon level in your household water.
Private well testing is necessary to know your home's water radon concentration
Because radon levels can vary significantly between wells, especially by depth and local geology, testing your own water supply is the only way to determine your specific radon level.
Consequences of Leaving Radon Untreated Over Time
Persistent radon in water can contribute to indoor air radon when water is used
Radon released from water during showers, cooking, or washing can add to indoor air radon, increasing exposure beyond soil gas entry.
Long-term exposure to elevated radon increases health risks as identified by authorities
Regulatory agencies recognize radon as a radioactive gas that, over extended periods at significant concentrations, may raise the risk of lung issues.
Radon Entry into Groundwater in Baltimore County
Natural uranium decay in local geology generates radon-222
Radon in this aquifer originates underground as uranium and radium minerals in rocks break down, releasing radon gas into water stored in fractures and porous spaces.
Deep wells capture water with dissolved radon gas
Wells 200 to 300 feet deep, like those sampled, draw groundwater that contains radon dissolved during its time underground.
Maintenance Rhythm of the Autotrol Radon in Water Filter
System ships ready to configure and requires routine monitoring
The Autotrol Radon in Water Filter arrives ready for user configuration. Regular checks of filter condition and performance ensure consistent radon reduction.
Periodic filter material replacement supports ongoing effectiveness
To maintain optimal function, filter media should be renewed at intervals aligned with water usage and radon load.
Sample Size and Data Scope Behind Radon Measurements
Median and range come from only three wells tested once each
The current figures are based on a small sample size; while useful for area trends, they have limited precision for individual risk estimation.
Variability between wells highlights need for personal water testing
The wide range of radon levels among sampled wells shows that localized geology and depth have strong influence, making individual testing the reliable option for households.
Importantly, these area-based radon measurements do not predict your home water's radon content. Testing your own well or water supply is necessary to assess your specific situation and determine if filtration, such as with the Autotrol Radon in Water Filter, is warranted.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2020-01-13. These figures describe groundwater sampled in this area. They are not a test of any individual private well - only a test of that well can establish its own water.
On record: U.S. Geological Survey sampling of Radon-222 in the 400BLMR aquifer (Baltimore County): 3 results from 3 wells, median 3470.0 pCi/L, range 227.0-4900.0 pCi/L; none above any federal threshold
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