Pentek Chromium-6 Filter

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When a lab report lists chromium-6, also known as hexavalent chromium or chromium(VI), it provides a concentration measured in micrograms per liter (µg/L or ppb). For the Kennebunk, Kennebunkport, and Wells public water system in York County, ME, federal occurrence monitoring from 2013 to 2015 showed chromium-6 was detected in 8 out of 12 samples above 0.03 µg/L, with the highest measurement at 0.19 µg/L; total chromium remained below detection limits for chromium above 0.2 µg/L in the same tests. These results reflect the water source and treatment for over 35,000 residents through more than 14,000 connections. No health-based violations were recorded by EPA for this system during that period.

1. Trivalent versus hexavalent chromium: why a total-chromium result cannot answer the question

Total chromium measurements sum all chromium species without distinguishing oxidation states. Chromium-6 (hexavalent chromium) and chromium-3 (trivalent chromium) differ in chemical behavior and potential health considerations. Because total chromium tests do not differentiate the forms, a non-detection in total chromium above 0.2 µg/L does not rule out the presence of chromium-6 at lower levels. For a precise understanding, testing must specifically measure chromium-6.

2. Why California set its own 10 µg/L limit and what that history means for a reader elsewhere

California established a public health goal of 0.02 µg/L and a regulatory limit of 10 µg/L for chromium-6, driven by scientific assessments and local occurrence data different from federal standards. The Kennebunk system’s detected levels are far below this threshold, reflecting no regulatory violation or exceedance in York County. However, this history illustrates why some households may consider treatment options for chromium-6 even when federal limits are not established or exceeded.

3. How oxidation state changes between the well, the distribution main and the tap

Chromium’s oxidation state can change due to water chemistry and treatment processes. Surface water sources supplying Kennebunk’s system generally undergo oxidizing conditions that may maintain chromium in its hexavalent state. Conversely, interactions within household plumbing—depending on materials and water characteristics—might influence chromium speciation. Understanding these variations can help explain differing chromium-6 levels between the main system and tap water, underscoring the importance of individual household testing.

4. Geogenic hexavalent chromium in arid and alkaline aquifers versus industrial plating sources

Hexavalent chromium may originate from natural (geogenic) sources or industrial activities. Geogenic sources typically appear in arid, alkaline aquifers where chromium is naturally released from rocks and sediments. Industrial sources involve chromium from manufacturing or plating operations. Since Kennebunk’s water comes from surface sources and has no recorded health violations, geogenic or industrial chromium-6 presence at low levels is plausible but not indicative of contamination requiring regulatory action.

5. The order in which to rule things out, from cheapest check to laboratory test

• Check water source documentation: Review your local water utility’s Consumer Confidence Report and EPA records for chromium-6 monitoring results relevant to your area.
• Consider water chemistry factors: Evaluate if household plumbing materials or recent maintenance could influence chromium speciation or levels.
• Conduct household specific testing: Arrange a certified laboratory test specifically for chromium-6 in your tap water to understand your home's precise condition.
• Assess treatment needs: Based on your test results and household demand, consider direct-purchase options such as the Pentek Chromium-6 Filter, a system designed to address chromium-6 concerns by targeting chromium(VI) effectively.

All figures and findings discussed here come from the Kennebunk, Kennebunkport & Wells Water Department public water system record reported under EPA’s Unregulated Contaminant Monitoring Rule 3 (UCMR3). This data represents system-wide monitoring, not individual household water tests. To know your home’s exact chromium-6 levels, direct laboratory analysis is necessary. For public data, visit EPA’s official database on drinking water quality.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2014-12-03. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA UCMR3 monitoring (2013-2015) for Kennebunk, Kennebunkport & Wells WD (ME0090760), ME: 24 results across 2 listed contaminants, 8 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L