Understanding California's Chromium-6 Limit and Its Broader Meaning
California established a public health goal for hexavalent chromium (chromium-6) at 10 micrograms per liter (µg/L), or parts per billion (ppb), based on toxicity studies suggesting potential risks at higher levels. This benchmark aims to guide water quality management and consumer awareness. While this standard applies within California, it is not a federal regulatory limit. For Lawrence households served by the City of Lawrence's surface water system, this means local chromium-6 levels can be compared to this health goal but do not indicate mandatory compliance or violation. Understanding this context helps frame what regional chromium-6 measurements imply for residential water use outside of California.
Household Fixtures and Uses Most Affected by Chromium(VI)
Chromium-6 presence in water can influence several household points of contact. Commonly impacted fixtures include kitchen taps, where drinking and cooking water is drawn, and bathroom faucets used for personal hygiene. Appliances such as ice makers and water dispensers are also areas where chromium(VI) may be a consideration due to direct consumption. Additionally, water used in showers and baths can lead to skin exposure. Households concerned about hexavalent chromium should prioritize these fixtures when evaluating potential water treatment or filtration options.
Evaluating Treatment Capacity Relative to Household Daily Demand
Effective response to chromium-6 concerns involves balancing filtration capacity with household water consumption. Residential water use varies daily depending on family size, appliance frequency, and lifestyle. Selecting a filtration method that aligns with these needs ensures consistent availability of treated water at key fixtures. It is important to estimate average daily usage to confirm that a chosen chromium(VI) filter can handle the volume without performance loss. Considering peak water use times, such as mornings and evenings, also aids in making a suitable choice for water treatment management.
Sample Size and Scope Behind Chromium-6 Data for Lawrence's Water System
The chromium-6 information for the City of Lawrence water system is based on 16 samples collected during the EPA's Unregulated Contaminant Monitoring Rule (UCMR3) between May 2013 and February 2014. These samples represent the system as a whole and not individual household taps or private wells. The system serves over 95,000 residents through more than 32,000 connections, providing a broad but generalized picture of chromium(VI) presence. A small number of samples, while informative, means localized variations could occur at individual homes. Testing at the tap is the only way to determine household-specific chromium-6 levels.
Seasonal and Multi-Year Trends in Chromium(VI) Levels within the City of Lawrence Water System
The chromium-6 data spans a time interval of about nine months, capturing conditions from spring 2013 through winter 2014. This snapshot shows some variation in hexavalent chromium concentrations, with detected values ranging from just above 0.03 µg/L up to 2.3 µg/L. Although this reflects a limited timeframe, it suggests chromium(VI) presence is persistent but may fluctuate with seasonal changes in water source composition or treatment processes. Multi-year data outside this period is not provided, so changes over longer terms cannot be assessed here.
Clarifying the Terms: 'Detected', 'Median', and 'Range' in Chromium-6 Sampling
In the EPA records, 'detected' means that chromium-6 concentration was measured above the reporting level of 0.03 µg/L; it does not imply unsafe or regulatory exceedance. The 'median' of detections, 1.165 µg/L for chromium-6, represents the middle value of detected concentrations from the 16 samples, indicating a central tendency but not a maximum. The 'range' indicates the lowest and highest detected levels across samples, here from just over the reporting limit up to 2.3 µg/L for chromium(VI). These figures describe what the instruments measured within the system but do not reflect individual household water quality.
Based on this data and the absence of any EPA health-based water quality violations for chromium, residents should not conclude that their own home's water contains these specific concentrations or that it is unsafe. To establish household water characteristics, testing of individual taps or private wells is necessary. For managing chromium-6 concerns at home, products such as the Pentek Chromium-6 Filter ship ready to configure to address hexavalent chromium through proven technology suitable for residential use.
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