Government sampling records from the U.S. Geological Survey show that wells in the 110AVMB aquifer under Doña Ana County have chloride concentrations ranging from 68.1 to 7,630 mg/L, with a median of 613 mg/L, based on seven samples taken from five wells between 2010 and 2017.
Reading Median and Range Values as a Homeowner
Looking at the median chloride level of 613 mg/L means that half the samples measured had chloride greater than this value and half had less, offering a midpoint for understanding typical groundwater quality. The range from 68.1 to 7,630 mg/L reveals a wide spread, indicating that some wells in this area exhibited much higher chloride than others sampled. However, these figures reflect only tested wells and do not indicate the chloride concentration in any individual well.
How Chloride Enters Groundwater in Doña Ana County
Chloride naturally occurs in the region's groundwater due to the geology and underlying soil minerals of the 110AVMB aquifer. Additionally, irrigation return flows, road salt application in colder months, and other human activities can influence chloride levels, but the exact balance varies by well location and depth. The sampled wells were 40 to 90 feet deep, reflecting typical domestic well depths in this area.
Understanding 'Detected,' 'Median,' and 'Range' in Sampling Results
'Detected' means the lab instruments measured chloride concentrations above their reporting limit in all seven samples collected from the area aquifer. The median provides a central value helping to summarize data. The range indicates minimum and maximum measurements across the samples. These statistical numbers describe conditions at sampled locations but cannot predict any individual well’s specific water quality.
Interpreting Chloride Levels Against Standards
The EPA secondary standard for chloride is 250 mg/L, serving as an aesthetic guideline relating to taste and potential staining rather than a health limit. Five out of seven samples exceeded this threshold, which suggests water in some wells may cause taste or staining issues, but this is not a violation and does not imply harm. It is important to note that these standards govern aesthetic quality, not safety.
Consequences of Leaving High Chloride Untreated
When elevated chloride in well water is left untreated, homeowners may notice salty taste, corrosion of metal plumbing components, and possible staining on fixtures or laundry over time. These effects can gradually impact household convenience and equipment longevity but do not indicate a health risk. Identifying and managing chloride levels helps maintain comfort and protect plumbing.
Next Steps: Testing Your Well and Considering Treatment Options
The definitive step is to obtain a current laboratory test of your own well water, focusing on chloride concentration to establish your specific conditions. Once your well’s chloride level is known, sizing a treatment solution becomes precise. The C-Series Total Well Chlorination System offers effective treatment, with a grain capacity of 32,000, and ships ready to configure for residential use. Evaluating your test results alongside the documented capabilities of this system will guide you in choosing the right fit for your home’s water treatment needs.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2017-02-23. 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 Chloride in the 110AVMB aquifer (Doña Ana County): 7 results from 5 wells, median 613.0 mg/L, range 68.1-7630.0 mg/L; 5 above an AESTHETIC secondary standard only (secondary standard 250.0 mg/L (aesthetic)) - not a health finding