If you live in Kootenai County, ID, you might notice chromium-6 in your water supply. Although your current water treatment setup may be handling general water quality, some households find it cannot fully address chromium-6 levels as identified by government studies.

Why California Established a 10 µg/L Limit and What That Means Here

California has set a public health goal and regulatory limit of 10 micrograms per liter (µg/L), equivalent to 10 parts per billion (ppb), specifically for chromium-6 in drinking water. This limit was established largely due to concerns over long-term health effects linked to chromium(VI). In contrast, the federal government has not set a maximum contaminant level (MCL) for chromium-6, focusing regulations on total chromium instead, which includes all forms up to 100 µg/L.

For residents in Kootenai County, this history serves as a reference point rather than a direct regulatory requirement. It highlights that even when chromium-6 is detected at levels below those set by California, households may still want to be informed and proactive based on individual needs and preferences.

Geogenic Chromium-6 Versus Industrial Plating Sources in Groundwater

Chromium-6 in this region primarily comes from natural geological sources, referred to as geogenic chromium-6, which occurs especially in groundwater influenced by arid conditions or alkaline aquifers. This differs from industrial chromium sources such as plating or manufacturing discharges, which generally create localized contamination hotspots rather than widespread occurrences.

Since Kootenai County’s groundwater is the water source for the City of Coeur d'Alene public system, chromium-6 detections reflect natural levels in the aquifer rather than industrial pollution. This informs treatment needs and expectations for homeowners evaluating their water.

What to Record Before Seeking Treatment Guidance

Before pursuing specific treatment options for chromium-6, households should gather detailed information including:

• Recent laboratory test results from a certified water-testing laboratory that specify chromium-6 concentration in micrograms per liter (µg/L) or parts per billion (ppb).
• Details about current water treatment equipment performance and any documented limitations in managing chromium-6.
• Water source information such as well depth, age, and local geological context.
• Any observed water aesthetic issues related to chromium, such as discoloration or taste changes, although these are not direct health indicators.

Collecting these data points enables more tailored recommendations and ensures treatment choices address specific household water characteristics.

How the C-Series Chromium-6 Filter Addresses This Constituent

The C-Series Chromium-6 Filter is designed to reduce chromium(VI) concentrations by applying specialized filtration technology that targets hexavalent chromium in residential water. This equipment ships ready to configure for point-of-entry or point-of-use application and complements existing water treatment setups that may struggle to manage chromium-6 as effectively.

Its design helps to lower chromium-6 to levels that meet homeowner expectations, supporting improved water quality where current equipment may fall short, based on certified testing results.

Interpreting Certified Laboratory Reports on Chromium-6

Certified lab reports for chromium-6 will show concentrations in micrograms per liter (µg/L) or parts per billion (ppb). When chromium-6 is detected, the report lists the measured value along with the laboratory's reporting limit, which typically falls around 0.03 µg/L.

The report may also include total chromium measurements alongside chromium-6 data. It is essential to distinguish between these: hexavalent chromium refers to chromium-6 specifically, while total chromium accounts for all chromium forms combined.

Significance of Sample Size and Data Reliability

Kootenai County’s chromium-6 data originates from 40 water samples collected by the City of Coeur d'Alene between 2014 and 2015. Of these, 39 samples showed chromium-6 detected above the reporting level, with a highest recorded value of 0.312 µg/L and a median detection of 0.193 µg/L.

While these findings indicate the presence of chromium-6 across the public water system serving over 54,000 people, they represent a relatively small sample set from a public system perspective. Homeowners should consider that individual well or tap water testing is necessary to understand their specific chromium-6 levels, as area data cannot define conditions at any single household.

What Not to Conclude from Regional Data

It is important not to interpret the detection of chromium-6 in Kootenai County’s public water system data as an indication that any one household's water contains the same levels or that it is unsafe. The system record shows no EPA health-based violations for chromium-6 or total chromium.

Detections reflect measured presence, not a health violation or unsafe condition. Each household should obtain certified laboratory testing of their own water source to gauge actual chromium-6 concentration and determine if additional water treatment like the C-Series Chromium-6 Filter is appropriate.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2015-06-09. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA UCMR3 monitoring (2013-2015) for City of Coeur d'Alene (ID1280053), ID: 80 results across 2 listed contaminants, 60 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L