Government sampling of the Pettis/Johnson/Saline Public Water Supply District #1, which serves roughly 1000 people across Saline, Johnson, and Pettis Counties in Missouri, shows that chromium-6 (also called hexavalent chromium or chromium(VI)) has been detected in several tests between 2013 and 2015. Of 32 samples analyzed, 15 showed chromium-6 at levels above the reporting level of 0.03 micrograms per liter (µg/L), with the highest measurement recorded at 0.94 µg/L (0.94 parts per billion, ppb). These findings are from a federal occurrence survey and are not compliance tests or health violation records.
Why California Set Its Own 10 µg/L (ppb) Limit and What That History Means for a Reader Elsewhere
California established a public health goal and a maximum contaminant level (MCL) for chromium-6 at 10 µg/L based on state-specific risk assessments. This level serves as a regulatory guideline for water systems in California but is not a federal standard. The federal government currently regulates only total chromium with an MCL of 100 µg/L, which includes all chromium forms but does not separately regulate chromium-6. For homeowners in Missouri, including those in Johnson, Pettis, and Saline Counties, this means that local or federal standards do not formally define chromium-6 limits, though California’s benchmark provides context for interpreting detected concentrations.
How Ion Exchange and Reverse Osmosis Differ in What They Do to Chromium(VI) Specifically
Chromium-6 is a form of chromium dissolved in water and can exist in various chemical forms depending on water chemistry. When considering water treatment options, it is important to understand how technologies address this constituent. Ion exchange systems use resins to exchange ions in water, often effectively removing hexavalent chromium depending on resin type. Reverse osmosis (RO) uses a semi-permeable membrane to physically filter out dissolved substances including chromium-6. Both methods have documented capabilities for reducing chromium(VI) in residential water supplies, but their effectiveness can vary by water composition and treatment setup. Either method ships ready to configure for household use without requiring professional plumbing services.
How the Constituent Enters Groundwater or the Distribution System in This Region
Chromium-6 can originate from both natural sources and industrial activities, making its way into surface water or groundwater supplies. In the Pettis/Johnson/Saline PWSD #1 system—which relies on surface water—chromium-6 presence likely reflects a mix of natural background levels and possible anthropogenic influences. Hexavalent chromium is water-soluble and mobile, allowing it to travel through soil and water bodies to reach the treatment system’s intake points. Seasonal changes and watershed conditions can also influence its concentration in the source water.
What 'Detected', 'Median' and 'Range' Mean in the Sampling Record on This Page
The term 'detected' means that analytical instruments measured chromium-6 at or above the reporting level of 0.03 µg/L but does not imply a health violation or unsafe condition. Among the 15 detected measurements, the median was 0.045 µg/L, which represents the middle value of all detections and is a central tendency rather than an average. The range spans from the lowest detection above the reporting level to the highest measured 0.94 µg/L, showing variability over the sampling period. These results provide an indication of presence and concentration fluctuations in the public water system but do not specify the level any individual household receives without separate testing.
How to Compare This Area's Record with a Neighbouring County's Without Overreading It
When reviewing chromium-6 data from nearby counties or water systems, it is essential not to interpret differences as definitive indicators of safety or hazard for a specific home. Sampling methods, water source types, and environmental factors vary and affect results. The Pettis/Johnson/Saline PWSD #1 data reflect a localized snapshot for a specific surface water system rather than a general regional baseline. Thus, comparing numeric values across counties should be done with caution, focusing on trends rather than absolute judgments, to avoid overreading the data.
How Public-System Records Differ from Private-Well Testing in What They Establish
Public water system records like those shown for Pettis/Johnson/Saline PWSD #1 report monitoring results averaged over many connections and sampling points, representing the system’s source and treated water. They do not reflect the water quality at any single home’s tap or private well. Private well owners should arrange individual water testing to know their own chromium(VI) concentrations accurately, as local geochemistry and plumbing characteristics can lead to differences. Public system data provide background information and a framework for understanding possible constituents in an area’s water.
In summary, the public water system serving Johnson, Pettis, and Saline Counties in Missouri has recorded detectable chromium-6 levels well below California’s 10 µg/L contextual benchmark and far below the federal total chromium MCL. Homeowners should consider testing their specific water to determine actual chromium(VI) presence. The C-Series Chromium-6 Filter offers a documented technology for households to address chromium-6 when desired, shipping ready to configure for personal water treatment needs.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2014-10-07. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Pettis/Johnson/Saline PWSD #1 (MO3021332), MO: 64 results across 2 listed contaminants, 21 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L