Understanding the Local Sampling Record for Arsenic
Recorded Arsenic Range
Five groundwater samples from four wells in the Douglas County aquifer 110SAGR show arsenic levels ranged between 4.0 and 11.0 micrograms per liter (ug/L).
Median Value Explained
The median arsenic concentration across these samples was 5.55 ug/L, reflecting the midpoint level found during sampling conducted between August 2022 and April 2026.
Detection Frequency
Arsenic was detected in four of the five samples, with one sample below the reporting limit, indicating occasional low or unmeasurable arsenic presence in the tested wells.
Steps to Assess Your Household Water
Start with Household Water Testing
Since area data cannot confirm your water’s arsenic level, a certified laboratory test of your own well or tap water is essential to establish exact concentration.
Check Well Depth
Sampled wells ranged from 50 to 279 feet deep; your well’s depth can influence arsenic presence but does not guarantee similar levels.
Consider Nearby Area Records
Use Douglas County’s area data as a reference point rather than a direct indicator of your water’s safety or aesthetic qualities.
Clarifying Sampling Terms
Meaning of "Detected"
Detection means arsenic was measurable by the instruments used, not that levels violate any health or safety standards.
What Median Represents
The median is the middle value of the dataset, showing a typical arsenic level found across sampled wells in this aquifer.
The Range of Values
The range between 4.0 and 11.0 ug/L indicates variability among samples, reflecting natural differences in groundwater arsenic concentration within the area.
Comparing Douglas County With Neighboring Areas
Use Regional Data Cautiously
Comparisons with adjacent counties can provide context but do not substitute for testing your specific water source.
Do Not Overinterpret Small Differences
Variations in median or range between counties often reflect sampling size or local geology and should not cause immediate concern.
Interpreting Certified Laboratory Reports
Laboratory Test Results
A certified test report will provide exact arsenic concentration for your water sample, enabling informed decisions on treatment options.
Understanding Reporting Limits
Results below the laboratory’s reporting limit indicate arsenic is present at very low or undetectable levels, not necessarily indicating safety or risk.
Reading Compliance Information
Federal arsenic thresholds set safety parameters; none of the area samples exceeded these limits. Your lab report will state if your result falls within these guidelines.
What Douglas County Data Does NOT Tell You
Area sampling data does not determine the exact arsenic level in your household water nor indicate health risk for your specific well or tap.
Only testing your water can confirm arsenic concentration and help you decide if treatment equipment fits your needs.
For households considering treatment, the Autotrol Arsenic Filter system ships ready to configure and offers a proven solution for reducing arsenic to meet your water quality goals.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2026-04-30. 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 110SAGR aquifer (Douglas County): 5 results from 4 wells, median 5.55 ug/L, range 4.0-11.0 ug/L; none above any federal threshold