Trivalent versus Hexavalent Chromium: Why Total Chromium Results Don’t Tell the Whole Story
A common misconception is that a total chromium result alone answers the question about chromium-6 presence in household water. Total chromium includes all forms of chromium in water, primarily trivalent chromium (chromium-III) and hexavalent chromium (chromium-6). While trivalent chromium is an essential nutrient in small amounts, hexavalent chromium (Cr(VI)) is the form often discussed for water quality concerns. The public water system record from Security WSD serving El Paso County reports chromium-6 detections in every sample between 0.03 and 0.89 micrograms per liter (µg/L), equivalent to parts per billion (ppb), with no federal maximum contaminant level set specifically for hexavalent chromium. Total chromium results range from 0.2 to 0.9 µg/L, well below the 100 µg/L total chromium MCL noted by the EPA. Because total chromium includes chromium-6 and chromium-III, this figure alone cannot define treatment requirements for chromium-6 specifically—a key factor when weighing treatment options.
Judging Treatment Capacity Against Household Daily Water Demand
Treating chromium-6 involves ensuring the selected method can handle the volume of water a household uses daily. Typical residential water use depends on household size, appliances, and landscaping needs, which vary widely. An effective treatment approach must accommodate peak and average usage without compromising performance. For chromium-6, technologies such as the C-Series Chromium-6 Filter ship ready to configure for residential setups, designed to match demand efficiently. Estimating daily usage helps determine whether a single filtration unit suffices or if additional capacity is necessary. Homeowners should consider this factor carefully when comparing alternatives, as underestimating demand can reduce treatment efficiency and overestimating can increase unnecessary complexity.
Seasonal and Multi-Year Variations in Chromium-6 Levels
The testing data collected by the EPA from 2013 to 2015 over 44 sampling events demonstrate some fluctuation in chromium-6 concentrations in Security WSD’s source water. The median measured value was 0.485 µg/L, with the maximum at 0.89 µg/L. Such variations may be influenced by changes in water source conditions, treatment plant operations, or environmental factors affecting surface water quality. Recognizing this variability is important for treatment planning since residential systems must consistently meet demand despite fluctuating input concentrations. The data confirms chromium-6 is regularly present but stable over multiple years, supporting the feasibility of selecting a treatment solution that targets this range efficiently.
Ruling Out Preliminary Factors: From Cost-Effective Checks to Laboratory Analysis
Before committing to chromium-6 targeted treatment, households should take stepwise actions to understand their water condition better. The lowest-cost check is reviewing local water system reports like the EPA’s public water system record for Security WSD to understand baseline levels. Following this, homeowners interested in more precise results may consider comprehensive laboratory analysis of their tap or well water for chromium-6, since only direct testing establishes individual water quality. This sequential approach helps measure whether a specialized chromium-6 filter is necessary or if other water quality factors might influence treatment choice. It also prevents unnecessary investment by confirming the presence and concentration of Cr(VI) specific to the household.
Differences Between Public System Records and Private Well Testing
Public water system monitoring provides a broad picture of chromium-6 levels affecting community water supplies but does not specify individual household water quality. The Security WSD system supplies surface water to roughly 20,000 people through over 7,500 connections, with chromium-6 detected consistently yet below levels of regulatory concern. Private well water, however, can vary significantly even within the same geographic area and may require independent testing for chromium(VI). Understanding this distinction is crucial: reliance solely on system-wide data can misrepresent a home's actual exposure. Therefore, residential water users in El Paso County considering chromium-6 treatment should balance the system’s monitoring data with their own testing to make fully informed decisions.
In summary, this page has clarified the importance of distinguishing hexavalent chromium from total chromium in evaluating water results, highlighted the role of daily household water use in treatment planning, and shown how consistent chromium-6 presence over several years influences treatment needs. It also outlined a logical path from reviewing public system data to conducting specific water tests, helping households select appropriate chromium-6 treatment options like the C-Series Chromium-6 Filter effectively.
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