What EPA's UCMR3 Survey Reveals and Its Household Limits
The City of Lawrence, serving Douglas County, participates in the EPA's Unregulated Contaminant Monitoring Rule 3 (UCMR3) survey conducted from 2013 to 2015, which measured chromium-6 in the public water supply sourced from surface water. This survey involved 16 samples all detecting chromium-6 at levels above the reporting threshold of 0.03 micrograms per liter (µg/L or ppb), with the highest reading at 2.3 µg/L and a median detection of 1.165 µg/L. Importantly, these measurements describe the public water system as a whole and do not reflect the specific water chemistry of individual homes. For anyone considering treatment, only a lab analysis of their own household water can determine the exact concentration of chromium-6 present.
Comparing Ion Exchange and Reverse Osmosis for Chromium(VI) in Water
When addressing chromium-6, also called hexavalent chromium or Cr(VI), two common treatment technologies stand out: ion exchange and reverse osmosis. Ion exchange methods specifically target the ions of chromium(VI), exchanging them with less harmful ions to reduce chromium levels. This approach can be efficient in removing chromium-6 from water but may require careful maintenance to ensure continued performance. Reverse osmosis, meanwhile, uses a semipermeable membrane to physically block chromium(VI) along with many other dissolved substances, producing purified water. It generally removes a broader range of contaminants but typically involves higher water waste and system complexity. Selecting between these technologies depends on your water demand, chromium concentrations, and other treatment goals.
California’s 10 µg/L Limit for Chromium-6 and Its Broader Significance
California has established a public health goal of 10 micrograms per liter for chromium-6 in drinking water, motivated by localized risk assessments and community health concerns. This limit is not a federal mandate but influences awareness nationwide. Lawrence’s public water chromium-6 levels measured under UCMR3 are below this California advisory benchmark, which can offer some context for residents evaluating treatment options. However, this state-specific limit reflects policy decisions made with local data and priorities and does not imply that water measured below it in other regions is unsafe or noncompliant with federal standards.
Understanding Measured Chromium Levels Against Federal Limits
The EPA's total chromium Maximum Contaminant Level (MCL) is set at 100 µg/L, significantly higher than chromium-6 concentrations detected in the Lawrence water system samples. While chromium-6 is a form of total chromium, there is currently no separate federal MCL specifically for hexavalent chromium. Thus, the detected chromium-6 levels do not indicate any violation or health-based exceedance. Detection simply confirms the presence of chromium(VI) at measurable amounts. Residents should interpret these data points as baseline information about system-wide water quality, not definitive statements on individual water safety.
Steps to Assess and Confirm Your Household Water Quality
To understand the chromium-6 level in your own home, start by reviewing any recent water quality reports from the local utility, which may include system-wide results. Next, a targeted laboratory test for chromium(VI) provides the most accurate data for your household. This approach helps distinguish your water’s specific chemistry from broader municipal measurements. Testing is the most cost-effective way before considering treatment; attempting equipment without verified need might lead to unnecessary expenses.
Once your water demand and chromium-6 concentration are known, the documented Autotrol Chromium-6 Filter, using an Autotrol system technology, ships ready to configure for residential use. It offers a reliable approach matched to measured chromium(VI) levels, helping households manage chromium-6 effectively as part of a balanced water treatment plan.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2014-02-19. 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 Lawrence (KS2004503), KS: 32 results across 2 listed contaminants, 29 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L