If You Know Why California Established a 10 µg/L Chromium-6 Guideline
California’s public health goal of 10 micrograms per liter (µg/L) for chromium-6 (hexavalent chromium) was set following studies that suggested potential risks from long-term exposure. This guideline is specific to California and is not a federal enforceable standard. For Brookfield’s water system in Waukesha County, Wisconsin, this means the local public water system is not subject to that limit, but the guideline provides a useful point of comparison when considering treatment.
Understanding this distinction helps households evaluate chromium(VI) in their water without assuming the California guideline applies directly to their situation.
If You Consider Why Total Chromium Results Cannot Confirm Chromium-6 Levels
Testing for total chromium does not distinguish between trivalent chromium (Cr(III)) and hexavalent chromium (chromium-6, Cr(VI)). Trivalent chromium is an essential nutrient in trace amounts, while hexavalent chromium has different chemical behavior.
Brookfield’s water system data from 44 samples showed no detection above 0.2 µg/L for total chromium and no detection above 0.03 µg/L specifically for chromium-6. However, these figures reflect detection limits of the method used and do not specify the exact chromium speciation in every sample.
If You Understand How Sample Size and Well Numbers Affect Confidence in These Data
The Brookfield Water Utility serves approximately 29,070 people through 10,766 connections, sourcing water from groundwater. The chromium-6 data come from 44 samples collected between 2014 and 2015 as part of the EPA’s third Unregulated Contaminant Monitoring Rule (UCMR3). This limited number of samples covers a portion of the system, giving an overview rather than a full constant profile of chromium(VI) presence.
Therefore, while no sample detected chromium-6 above 0.03 µg/L, individual wells or household taps may vary. Home testing is advisable to determine specific water quality where you live.
If You Know What These Sampling Ranges Mean Against Relevant Federal Standards
The federal maximum contaminant level (MCL) for total chromium is 100 µg/L (equivalent to parts per billion). The Brookfield system’s detected chromium-6 and total chromium results are well below this value, with no federal MCL established for hexavalent chromium specifically.
This means that the reported measurements do not represent violations or unsafe conditions under federal law. Instead, they describe chromium concentrations that are very low or below the analytical reporting limits during sampling periods.
If You Are Considering the Role of Plumbing Materials Separate From Source Water Quality
Household plumbing can influence chromium levels at the tap independently from source water. Older plumbing materials or certain pipe types may contribute to metal concentrations or affect water chemistry. Thus, assessing chromium-6 presence in your water may require targeted tap testing rather than relying only on public water system data.
This distinction is critical when comparing treatment options, since source water treatment and point-of-use solutions address different parts of the water supply path.
If You Are Reviewing This Data to Decide How to Address Chromium-6
Given the Brookfield Water Utility’s chromium-6 findings, if you wish to proactively manage chromium(VI) at home, a water treatment device using specialized filtration technology designed to target hexavalent chromium can be considered. The C-Series Chromium-6 Filter ships ready to configure for residential use and focuses on addressing chromium-6 as measured in water.
Before choosing a treatment approach, verify your individual water through proper testing since local variations exist beyond public system averages.
These public water system figures reflect sampling from 2014 to 2015 and are documented by the EPA’s Safe Drinking Water Information System (SDWIS) for Brookfield, Waukesha County. For more detailed, up-to-date information visit the EPA data repository directly.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-03-18. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Brookfield Water Utility (WI2680253), WI: 88 results across 2 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level