What 'detected', 'median' and 'range' mean in the sampling record on this page
The U.S. Geological Survey has sampled groundwater from wells in Benton County’s aquifer 124WLCXU, finding pH values consistently below the secondary standard range set by the EPA. In this record, 'detected' indicates the pH was measurable in all four samples, with no readings below the detection threshold. The 'median' of 5.35 standard units represents the middle value in these pH measurements, while the 'range' from 5.2 to 6.0 standard units shows the span observed across the four samples from one well. These figures come from wells 22 feet deep and reflect conditions at that depth over an 11-year period rather than a single test for any specific household.
A worked example: reading the record's median and range as a homeowner would
Imagine reviewing this data when considering your home's water chemistry. The median pH of 5.35 suggests that acidic conditions are typical for the sampled location. However, the range—from 5.2 (more acidic) up to 6.0 (closer to neutral)—shows that water acidity can vary even in nearby groundwater. Since these values fall below the EPA’s secondary pH standard (6.5 to 8.5), they indicate that, regionally, water may lean acidic, which can affect household plumbing and water taste. Still, your own household water chemistry may differ and requires testing to confirm.
Why aesthetic secondary standards differ from health-based limits, applied to this constituent
EPA’s secondary standards for pH are designed to address aesthetic and corrosivity concerns rather than health risks. This means that while low pH can influence water taste, cause staining, or accelerate pipe wear, it is not considered a safety issue by regulatory definitions. The Benton County aquifer samples fall below the 6.5 to 8.5 pH range recommended for aesthetics and corrosion control, but this does not indicate unsafe water. Understanding this difference helps households focus on what pH impacts—such as plumbing lifespan or water taste—when evaluating treatment needs.
How sample depth, well depth or source type changes what a reader should expect
The reported pH values stem from groundwater wells just 22 feet deep, which can be more influenced by local geology, soil composition, and natural acids than deeper aquifers or surface water sources. Different depths and water sources may show varying pH levels due to oxygen availability, mineral content, and other factors. Households drawing from deeper wells or different aquifers in Benton County could experience different acidity levels. Testing your specific water source is essential to determine its characteristics.
How seasonal or multi-year variation shows in the record (dates and ranges given)
The data covers an 11-year span from 2011 to 2022, providing insight into the stability and variation of pH over time. The narrow range of 5.2 to 6.0 across four samples suggests relative consistency in acidity for this particular well, though broader sampling might find wider seasonal fluctuations influenced by rainfall, temperature, and soil processes. Understanding these temporal patterns helps homeowners anticipate if their water's pH might change with seasons or years.
What you should NOT conclude from area data
While these regional measurements point to acidic groundwater conditions typical of Benton County’s aquifer 124WLCXU, they do not reveal your household’s specific water chemistry. The presence of low pH in sampled wells is not a violation, health concern, or direct indication of your water quality. Only direct testing of your home water can clarify its acidity and guide treatment choices. For households considering technical solutions to acidic water, options such as the Fleck Acidic / Low-pH Water Filter ship ready to configure and offer targeted correction based on specific water characteristics rather than area averages. Relying on regional data alone risks assumptions that may not fit your situation.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2022-06-01. 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 pH in the 124WLCXU aquifer (Benton County): 4 results from 1 wells, median 5.35 standard units, range 5.2-6.0 standard units; EPA secondary standard for pH is 6.5-8.5 (aesthetic/corrosivity, not health-based); 4 of 4 sampled results fell below 6.5
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