Purpose and Limitations of the UCMR3 Nationwide Chromium-6 Survey
The EPA’s Unregulated Contaminant Monitoring Rule 3 (UCMR3) survey conducted between 2013 and 2015 aimed to gather data on contaminants not yet regulated nationally, including chromium-6 (hexavalent chromium or chromium(VI)). The survey collected results from public water systems like the Western Virginia Water Authority that serves Roanoke City. While this survey provides broad information about likely presence and concentration ranges of chromium-6 in the system’s surface water supply, it does not reflect the water quality at any specific residential tap. Individual plumbing, local pipe conditions, and well water (if applicable) can differ. To know your household’s chromium-6 precisely, targeted testing of your water source is necessary.
California’s 10 Micrograms per Liter Threshold: Context for Chromium-6 Limits
California set a public health goal for chromium-6 at 10 micrograms per liter (µg/L, equivalent to parts per billion or ppb), motivated by research on potential health effects. This value guides water suppliers toward managing chromium-6 but is not a federal mandate. Roanoke City’s water system data does not indicate chromium-6 concentrations at this level. Understanding California’s limit helps households appreciate what levels elsewhere might signify but does not establish a legal or safety standard for Virginia residents.
Public Water System Records versus Private Well Testing
Records from the Western Virginia Water Authority represent samples taken at treatment plants or distribution points and summarize conditions across many connections—more than 67,000 in Roanoke City. Such records can confirm whether chromium-6 has been detected in the system and illustrate typical ranges, but they cannot specify concentrations in any one home. Private wells, or homes on different water systems, can have very different chromium-6 levels due to local geology or contamination sources. Homeowners should consider testing their own water if concerned, as system data alone does not establish individual water quality.
Fixtures and Water Uses First Affected by Chromium-6 Presence
Chromium-6 in water primarily becomes a concern when ingested or inhaled via aerosols during showering or other water use. Appliances that use water without filtration may experience minor impacts, but chromium-6’s main concern relates to long-term exposure via drinking and cooking water. Point-of-entry solutions can treat all incoming water, while point-of-use options target specific taps or fixtures. Knowing where chromium-6 impacts your household’s water use depends on your water source and treatment practices.
Interpreting Detected Chromium-6 Levels Against Federal Standards
EPA’s UCMR3 monitoring for Roanoke City’s Western Virginia Water Authority showed chromium-6 detections in 45 out of 57 tests, with results ranging up to 0.8 µg/L and a median detection of 0.13 µg/L (ppb). These figures fall well below the federal maximum contaminant level (MCL) of 100 µg/L for total chromium, which accounts for different chromium forms including chromium-6. Importantly, the absence of federal MCLs specifically for chromium-6 means these detections are measurements, not violations or safety exceedances. They indicate presence but do not define risk or health status for residents. Understanding the difference between detection and a regulatory limit clarifies what action may be warranted.
Confirming Your Water’s Chromium-6: The Essential Test
The only way to know the chromium-6 concentration in your household water is to have your water tested by a certified laboratory for chromium-6 specifically. This test will provide a precise measurement in micrograms per liter (ppb) that applies just to your tap. If the result is near or above levels of concern such as California’s 10 µg/L guideline, options are available to reduce chromium-6 exposure at home. Among these, the C-Series Chromium-6 Filter ships ready to configure and is designed to address chromium-6 in residential water supplies. Knowing your specific water chemistry through testing is the first and most important step.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-12-17. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Western Virginia Water Authority (VA2770900), VA: 114 results across 2 listed contaminants, 78 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L