What the measured pH range means against the federal secondary standard, and what it does not mean

Acidity is measured by pH, not a single fixed value

The U.S. Geological Survey sampled groundwater in Fayette County’s aquifer 327KNWH, finding pH values ranging from 5.7 to 7.3 standard units. The Environmental Protection Agency's secondary standard for pH is 6.5 to 8.5. This range is set to address aesthetic issues like taste and plumbing effects, not health risks.

Low pH readings indicate acidic conditions but not a safety violation

Half of the sampled results fell below the lower limit of 6.5, indicating acidic water in some wells. However, this is a secondary standard, so readings below 6.5 do not mean the water is unsafe; they suggest potential for taste changes or pipe corrosion.

Differences between public-system records and private well testing

Public records reflect averages from multiple wells, not individual household water

The Fayette County data represent six samples taken from three wells several feet deep. They provide a regional picture rather than exact conditions of a specific home’s water supply.

Private well testing is necessary for personalized water assessment

Because water chemistry can vary within a region and even between wells on the same property, households should obtain certified laboratory testing to understand their own water’s pH specifically.

What a certified laboratory report for pH includes and how to interpret it

Lab results provide precise pH measured from a water sample

Tests report pH as a number on the scale from 0 to 14, with lower values indicating acidity. A lab result below 6.5 means the water is acidic according to EPA secondary standards.

Interpretation focuses on potential impacts, not health hazards

Since acidity affects taste and can corrode pipes, a low pH result suggests considering water treatment options to protect plumbing and improve water quality experience.

How well and sample depth influence expected pH values

Depth of sampled wells in Fayette County ranged from 55 to 289 feet

Groundwater chemistry, including pH, can change with depth due to varying geological formations and mineral content. Deeper wells may show different acidity levels than shallower sources.

Water source type also affects acidity expectations

Aquifers with certain rock types may produce naturally more acidic water. Knowing well depth and local geology helps anticipate water characteristics.

Meaning of detected, median, and range in the sampling record

Detected means that pH was successfully measured in all samples

None of the samples fell below the reporting limit, meaning pH values were measurable and reliable.

Median value summarizes the middle pH in all samples

The median pH of 6.4 indicates that half the measurements were below this level and half above.

Range shows variation between lowest and highest pH values

The range of 5.7 to 7.3 highlights the natural variability in groundwater acidity within Fayette County's aquifer.

Worked example: reading Fayette County’s pH data as a homeowner

Consider the median pH of 6.4

This median suggests that your water could be slightly acidic compared to EPA’s secondary range, but individual testing is essential to confirm.

Note that some wells had pH as low as 5.7

Should your water test near this lower end, treatment addressing acidic water may be beneficial to prevent potential plumbing effects.

Recognize that other wells measured pH values in or above the acceptable range

This variability means acidic conditions are possible but not guaranteed in your specific well or tap.

Summary

Regional pH data for Fayette County’s aquifer indicate occasional acidic water conditions by EPA secondary standards, which relate to taste and corrosion concerns rather than safety. To understand your home’s water quality precisely, a certified laboratory test is recommended, and if acidic water is confirmed, solutions like the C-Series Acidic / Low-pH Water Filter ship ready to configure to address these concerns.

Where this information comes from

Source: USGS groundwater sampling. Sampled 2016-08-23. 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 pH in the 327KNWH aquifer (Fayette County): 6 results from 3 wells, median 6.4 standard units, range 5.7-7.3 standard units; EPA secondary standard for pH is 6.5-8.5 (aesthetic/corrosivity, not health-based); 3 of 6 sampled results fell below 6.5