Seasonal and Multi-Year Variation in Radon Measurements

Sampling Dates Show Consistent Detection

Radon was detected in eight groundwater samples collected between October 12, 2022, and July 2, 2024, from three separate wells in Cape May County’s aquifer 121CKKD. The samples, taken from wells 15 to 90 feet deep, consistently showed radon presence with values ranging from 50.0 to 88.0 picocuries per liter (pCi/L), and a median value of 65.0 pCi/L. This consistency suggests radon presence is a stable characteristic of the local groundwater rather than an isolated or short-term event.

Understanding Natural Fluctuations

Such variation between individual measurements is normal due to changes in water table levels, well depths, and other environmental factors. These fluctuations should not be mistaken for threats or violations but rather as part of the natural geochemical variation in the region.

Distinguishing Aesthetic Guidelines from Health-Based Limits for Radon

Detected Levels Do Not Exceed Federal Thresholds

Although radon was consistently detected, no measurement exceeded federal thresholds established for radon in water. It's important to understand that detection alone does not equate to a violation or unsafe condition.

Different Standards Address Different Concerns

Federal thresholds for radon balance considerations of health risk and practical water treatment. While some aesthetic secondary standards exist for other constituents influencing taste or staining, radon regulations focus on health-based criteria. This distinction means the presence of radon at detected levels is monitored but not deemed unsafe by these criteria.

Additional Considerations for Commercial and Industrial Water Users

Volume and Exposure Increase Complexity

Commercial or industrial operations may require analysis of radon levels with regard to water volume use, airborne radon release during water handling, and employee exposure risks. These factors add layers of regulatory and operational considerations not typical for household water use.

Specialized Testing and Controls May Be Necessary

Such water users often undertake more frequent or comprehensive radon testing, possibly consulting local environmental authorities. Treatment approaches may be tailored to larger volumes and different exposure scenarios compared to residential solutions.

Careful Comparison with Neighboring Counties to Avoid Overreading

Radon Levels Vary Geographically

Radon concentrations in groundwater can significantly differ even between adjacent counties, reflecting underlying geology. For example, comparing Cape May County’s aquifer levels with neighboring regions requires attention to sampling methods, well depths, and date ranges to avoid misleading conclusions.

Recognize Limits of Regional Data for Individual Wells

While area-wide measurements provide useful context, they do not define the condition of any specific private well. Only individual water testing can determine the exact radon concentration a household experiences.

Household Signs That May or May Not Indicate Radon

What Is Not a Reliable Indicator

Radon is a colorless, odorless gas dissolved in water and does not cause taste or staining. Homeowners should not rely on visual or sensory clues alone to identify radon presence in water.

When to Consider Testing

Testing is the only way to know radon levels in a household water supply. Given the presence of moderate radon concentrations in the local aquifer, testing is reasonable when water is from a private well drawing from this aquifer.

What You Should NOT Conclude from Area Radon Data

Government data show that radon is present in groundwater in Cape May County aquifer 121CKKD at levels below federal action thresholds. This means no sample from this area exceeds established health-based limits. It does not mean any specific household’s water matches these values or that radon presence alone indicates a health risk without further testing.

For households concerned about radon, water testing through a certified laboratory is essential to understand actual exposure. Should treatment be desired, products like the C-Series Radon in Water Filter ship ready to configure and can address radon removal effectively.

Where this information comes from

Source: USGS groundwater sampling. Sampled 2024-07-02. 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 121CKKD aquifer (Cape May County): 8 results from 3 wells, median 65.0 pCi/L, range 50.0-88.0 pCi/L; none above any federal threshold