Government sampling conducted within the Rockford public water system in Winnebago County, Illinois, shows that chromium-6 was detected in roughly half of the samples taken during 2014-2015, but no health-based violations have been reported for this water system.
Belief: Chromium-6 measurements come from many wells, making the data highly representative
The 54 water samples in this monitoring effort come from groundwater sources serving over 147,000 people through more than 51,000 connections. However, these samples represent a limited number of wells and times. A smaller sample size means individual home water conditions may vary significantly from these statistics.
Belief: Sampling depth and water source type do not impact chromium-6 levels noticeably
Since Rockford’s water system is supplied entirely from groundwater, data reflects conditions in wells tapping into underground aquifers. The depth of these wells and the specific hydrogeology can influence chromium-6 concentrations, so different homes drawing from other depths or sources may observe different levels.
Belief: Absence of chromium-6 detections means no potential concern at home
Chromium-6 can be present at low levels that vary over time. Because municipal data averages multiple sites and dates, a household should not assume zero presence based solely on nondetection in the system records. The most practical way to know about your home's water is to conduct a certified laboratory test of your own tap water.
Belief: Laboratory reports for chromium-6 are straightforward and always show a clear risk level
Certified laboratory tests measure chromium-6 concentration in micrograms per liter (µg/L), reporting values relative to established detection limits. These results do not establish regulatory violation or health risk by themselves, since no federal maximum contaminant level currently exists for chromium-6. Interpretation requires understanding detection limits, median values, and the difference between total chromium and chromium-6 measurements.
Belief: You can seek treatment advice without any specific water quality data
Before considering treatment options, it is important to record your water source type, the date and location of any water quality tests, and any relevant system or well information. This information helps in selecting appropriate water treatment equipment with verified capability against chromium-6.
For homes in Rockford concerned about chromium-6, the C-Series Chromium-6 Filter ships ready to configure and is documented to reduce hexavalent chromium where present. Remember that the public water system record reflects groundwater supply for many users; individual well or tap testing is essential for personalized decisions. The data summarized here comes from the EPA's Unregulated Contaminant Monitoring Rule (UCMR3) public water system record for Rockford, accessible through the EPA’s website.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-12-09. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Rockford (IL2010300), IL: 108 results across 2 listed contaminants, 34 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L