Residential Chromium-6 Concerns in El Paso Water and Managing Concentrations with Advanced Filtration

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Trivalent Versus Hexavalent Chromium: Why a Total-Chromium Result Cannot Answer the Question

The chromium found in water exists mainly in two forms: trivalent chromium (Cr(III)) and hexavalent chromium (Cr(VI), commonly called chromium-6). Total chromium tests do not distinguish between these forms. This matters because Cr(VI) differs chemically and in potential water treatment needs from Cr(III). Since total chromium levels incorporate both forms, relying solely on total chromium results cannot clarify whether chromium-6 is a concern for your household.

What 'Detected', 'Median' and 'Range' Mean in the Sampling Record on This Page

The EPA’s 2013-2015 Unregulated Contaminant Monitoring Rule (UCMR3) recorded chromium-6 in all samples from the Security Water District system serving about 20,000 people in El Paso County. Each result was above the detection level of 0.03 micrograms per liter (µg/L or parts per billion), with values ranging up to 0.89 µg/L and a median around 0.485 µg/L. These numbers reflect measurable presence, not a violation or unsafe condition, since no federal maximum contaminant level applies to hexavalent chromium, and total chromium remained far below its 100 µg/L limit.

What Happens When This Problem Is Left Untreated for Years, Stated Without Exaggeration

When chromium-6 remains in household water without targeted treatment, its measurable presence persists. While there is no EPA health-based violation in the municipal records, some households may notice potential aesthetic issues, such as slight changes in taste or appearance. The long-term accumulation of chromium-6 in water systems can pose challenges for treatment devices not designed to specifically address this form, leading equipment to struggle to maintain desired water quality levels over time.

How Oxidation State Changes Between the Well, the Distribution Main and the Tap

Chromium’s oxidation state can evolve due to water chemistry and treatment processes. Source water drawn from surface supplies in El Paso County introduces chromium-6, which can partially convert to other chromium forms within the distribution mains and eventually at the tap. This transformation depends on factors like pH, organic matter, and disinfectant use in the system. Therefore, laboratory testing of tap water from your household provides the most accurate picture of your water’s chromium-6 status, as distribution changes may alter chromium speciation.

The Order in Which to Rule Things Out, from Cheapest Check to Laboratory Test

• First, check whether your current water treatment equipment is rated specifically to address chromium-6 or hexavalent chromium compounds.
• Next, review recent water quality reports from Security Water District to understand typical chromium-6 detection levels in your area.
• If concerns persist, consider arranging for a certified laboratory to perform chromium-6 specific analysis on your household tap water, distinguishing Cr(VI) from total chromium.
• Evaluating equipment performance against chromium-6 levels helps determine if supplemental treatment may be needed to maintain desired water quality consistently.

When existing equipment cannot keep up with chromium-6 concentrations, options designed to target hexavalent chromium specifically can help.

In summary, understanding the difference between chromium forms, EPA data interpretations, and how to confirm your household water’s chromium-6 content are key steps. This approach guides responsible decisions when considering advanced filtration technologies such as the Pentek Chromium-6 Filter, which ships ready to configure for residential use.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2014-10-27. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA UCMR3 monitoring (2013-2015) for Security WSD (CO0121775), CO: 88 results across 2 listed contaminants, 80 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L