Radon in Cumberland County Water: Understanding Seasonal Variation and Testing for Residential Needs

Cumberland County in New Jersey relies on groundwater from aquifer 121CKKD, where water is drawn from depths ranging from 11 to 171 feet. Water flows through soil and rock before reaching household taps, potentially carrying dissolved gases and minerals such as radon-222. Understanding radon behavior in this aquifer helps homeowners manage its presence effectively.

How Does Radon Concentration Vary Over Time in Cumberland County’s Aquifer?

The U.S. Geological Survey sampled 24 wells in this aquifer between September 2022 and August 2024. Radon was detected in all 39 results, with concentrations ranging from 36.0 to 3900.0 pCi/L and a median of 189.0 pCi/L. This sampling period covers nearly two years, showing seasonal and multi-year variation in radon presence within this area.

These fluctuations are typical because radon levels in groundwater can change with temperature shifts, precipitation patterns, and changes in groundwater flow. It is important to interpret these figures as area-wide data, not specific to any single well.

How Should Residents Compare Radon Levels Here to Neighboring Counties?

While neighboring counties may have similar geological characteristics affecting radon levels, each area varies. Cumberland County’s record indicates a consistent detection of radon within a broad range, but comparisons should consider sampling methods, aquifer depth, and local geology. Adjacent counties may have different median or range values, yet these differences do not necessarily predict an individual household’s water quality.

Homeowners should use regional data as a guide, understanding that localized conditions can deviate significantly.

What Does a Certified Laboratory Test Report About Radon in My Water?

Testing for radon involves collecting a water sample under controlled conditions and measuring radon-222 concentration, typically expressed in picocuries per liter (pCi/L). A certified lab report will show your sample’s measured concentration, the detection limit, and any applicable comparison levels. The report does not label a detection as a violation; rather, it provides data for informed decisions.

Knowing your well’s specific radon level is the only way to determine how it compares with the regional findings from Cumberland County’s aquifer.

How Does Radon Enter Groundwater or the Water Distribution System in This Region?

Radon is a naturally occurring radioactive gas formed by the decay of uranium in soil and rock. In Cumberland County, radon enters groundwater as it moves through uranium-containing geological formations. Because radon is a gas, it can dissolve into water and persist while underground, then release into air when water is agitated or heated in a household.

Municipal water systems draw from this groundwater, but treatment and aeration practices influence radon presence at the tap. Private wells may directly reflect aquifer radon concentrations.

What Steps Should I Take to Evaluate Radon in My Household Water?

• Check existing equipment capacity. If current radon treatment or mitigation is in place but seems overwhelmed, capacity or maintenance should be reviewed.
• Start with easy, low-cost tests. Simple radon air tests inside the home can indicate if waterborne radon is contributing to indoor levels.
• Proceed to certified laboratory testing of water. A lab report provides accurate and specific radon levels for water from your well or tap.
• Consider a documented treatment system. For households needing enhanced radon reduction beyond current systems, a C-Series Radon in Water Filter ships ready to configure your water’s radon control needs.

This record reflects government sampling of groundwater wells in Cumberland County’s aquifer 121CKKD over nearly two years, offering a reliable picture of radon occurrence in the area but not individual household water. For more detailed data, refer to the U.S. Geological Survey monitoring location 391427075013001.

Where this information comes from

Source: USGS groundwater sampling. Sampled 2024-08-13. 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 121CKKD aquifer (Cumberland County): 39 results from 24 wells, median 189.0 pCi/L, range 36.0-3900.0 pCi/L; none above any federal threshold