What the Measured Range Means Against the Federal Standard, and What It Does Not Mean
Groundwater samples collected from Eagle County’s aquifer 111VLFL show arsenic present at concentrations between 0.05 and 0.13 micrograms per liter (µg/L), with a median of 0.09 µg/L. These results are from multiple wells sampled over more than a decade by the U.S. Geological Survey. Importantly, none of these concentrations exceed any federal arsenic thresholds. This means the area’s groundwater does not violate regulatory limits set to protect health. However, presence does not necessarily equate to risk or safety. Detection simply indicates that instruments measured arsenic; it does not imply it is unsafe or a violation.
How Sample Depth, Well Depth, or Source Type Changes What a Reader Should Expect
The wells sampled in this area vary in depth from 18 to 200 feet. Arsenic levels can vary with depth because groundwater chemistry changes with geological layers. Therefore, a shallower well might yield different arsenic results than a deeper one. Additionally, source types such as wells tapping confined aquifers versus shallow water tables can influence the arsenic presence. The regional data provide a general view but cannot predict individual well conditions. To understand arsenic in specific household water, direct testing of that source is necessary.
How Seasonal or Multi-Year Variation Shows in the Record (Dates and Ranges Given)
The sampling dates cover from May 25, 2010, to February 7, 2023, demonstrating a multi-year record. Arsenic detections occurred in 7 of 9 samples, with two samples below the reporting limit. The range and median remained fairly consistent over this period, indicating limited large fluctuations in arsenic at the sampled wells. Seasonal patterns are not strongly evident in these data, but individual wells might experience changes depending on local hydrology and water use.
What 'Detected', 'Median' and 'Range' Mean in the Sampling Record on This Page
"Detected" indicates that arsenic was measured above the instrument’s reporting limit. It does not indicate a health violation or unsafe condition. The "median" is the middle value in the set of arsenic measurements, representing a typical concentration in the sampled wells. The "range" shows the span from the lowest to highest measurements recorded, helping to understand variability. Together, these terms describe the general presence and variation of arsenic in the regional groundwater, not the specific quality of any one well or tap.
How the Documented Treatment Technology Removes or Neutralises the Constituent
For homeowners seeking to address arsenic in their water, specialized filtration systems directly purchased and shipped ready to configure can reduce arsenic concentrations. The Pentair Arsenic Filter employs media designed to remove arsenic effectively from water supplying a household. This technology traps arsenic particles as water flows through, lowering arsenic levels before water reaches taps. Users configure and maintain the system according to guidance to sustain treatment efficiency.
What the Reader Should Not Conclude from Area Data
Area-wide arsenic levels measured by the U.S. Geological Survey indicate the typical arsenic presence in the aquifer but do not define the condition of any single well or household’s tap water. Individual water sources may differ significantly based on depth, construction, and local geology. Only direct laboratory testing of a home’s water supply can determine its arsenic content accurately. The detected arsenic in Eagle County’s aquifer 111VLFL remains well below federal thresholds and is not a direct indication of risk without site-specific data.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2023-02-07. 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 Arsenic in the 111VLFL aquifer (Eagle County): 9 results from 5 wells, median 0.09 ug/L, range 0.05-0.13 ug/L; none above any federal threshold