Government sampling provides insight into uranium presence in groundwater around Madison County, Illinois, specifically within the 110QRNR aquifer. However, these area-wide data do not specify uranium concentrations in any individual household’s water supply. To know your own water’s condition, laboratory testing on your specific well or system is necessary. This page clarifies what the U.S. Geological Survey findings tell you and how that fits with federal guidelines and regional groundwater characteristics.

What changes for a large household, a second home, or a seasonal property?

Larger households or residences used seasonally may experience different water usage levels that affect how long treatment equipment functions before requiring replacement or maintenance. The uranium concentrations measured in the region do not vary by home size, but water demand influences treatment capacity needs. For example, the Pentair Uranium & Radium System, which ships ready to configure, has a grain capacity of 32,000, suitable for typical household volumes but with considerations for heavier usage or intermittent occupancy.

How does seasonal or multi-year variation show in the record (dates and ranges given)?

The U.S. Geological Survey collected 14 uranium measurements from 11 distinct wells between July 19, 2011, and August 23, 2023. This timeframe captures potential seasonal or annual changes in uranium detection. The range of uranium found spans from 0.026 to 11.5 micrograms per liter (µg/L), with a median of 1.18 µg/L. The data indicates consistent detection over the years but does not by itself establish temporal trends or predict short-term fluctuations at any individual well.

How many samples and wells stand behind the figures, and what does a small sample mean?

The dataset includes 14 results from 11 separate wells sampled within the aquifer depth range of 17 to 102 feet. This sample size offers a general picture of uranium presence in the area aquifer but is limited in coverage and depth distribution. Small samples cannot represent all local variations; individual wells may differ substantially in uranium levels. Therefore, area sampling informs regional assessments but cannot substitute for direct testing of your water source.

What does the measured range mean against the relevant federal standard, and what does it not mean?

None of the uranium concentrations measured in these Madison County wells exceeded federal thresholds for uranium in drinking water. This means the levels found in area wells do not violate established health-based standards. However, detection alone is not a violation or a health risk indicator. The presence of uranium requires monitoring but does not confirm unsafe water. Only a certified laboratory test on your water can determine compliance and safety specific to your home.

How does uranium enter groundwater or the distribution system in this region?

Uranium naturally occurs in the earth’s crust and can dissolve into groundwater as it moves through mineral-bearing rocks and sediments. In Madison County’s aquifer 110QRNR, the uranium detected likely originates from these natural geological sources rather than contamination events. It seeps slowly into groundwater supplies, influenced by local mineralogy and hydrological conditions. Municipal distribution systems generally treat source water to meet regulatory standards and maintain safety.

What do 'detected,' 'median,' and 'range' mean in the sampling record on this page?

• Detected means the instrument measured uranium present above the reporting limit in all 14 samples, confirming consistent presence in sampled groundwater.
• Median refers to the middle value (1.18 µg/L) in the ordered dataset, representing a central tendency of uranium measurements across wells.
• Range shows the spectrum of results from the lowest (0.026 µg/L) to the highest (11.5 µg/L) uranium concentrations found in the area wells sampled.

This terminology helps understand uranium occurrence broadly but does not specify individual well conditions.

In summary, the data set reflects uranium levels measured by the U.S. Geological Survey in Madison County’s aquifer 110QRNR over a 12-year period and from multiple wells of varying depths. These figures do not determine the uranium content in individual household water. Homeowners concerned about uranium should obtain certified laboratory testing for their own water source. For households needing treatment options, the Pentair Uranium & Radium System is a documented solution that ships ready to configure and addresses uranium and radium within typical treatment requirements.

For detailed data, visit the official U.S. Geological Survey monitoring location: https://waterdata.usgs.gov/monitoring-location/384714089585301/

Where this information comes from

Source: USGS groundwater sampling. Sampled 2023-08-23. 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 Uranium in the 110QRNR aquifer (Madison County): 14 results from 11 wells, median 1.18 ug/L, range 0.026-11.5 ug/L; none above any federal threshold