The Fort Defiance/Window Rock/St. Michaels system serves water to numerous households in NN county through a network of public water connections. This regional system draws from sources monitored regularly by the Environmental Protection Agency (EPA) under the Unregulated Contaminant Monitoring Rule (UCMR3). Water is treated and distributed, reaching household taps with water quality subject to this system's recorded performance.
If You Notice Water Quality Concerns but See No Health-Based Violations
The EPA record for this water system reports no health-based violations related to chromium-6 or total chromium. This means the system complies with federal safety benchmarks for these substances. However, chromium-6 presence was detected in 13 of 20 samples between 2014 and 2015, ranging from just above the reporting level of 0.03 micrograms per liter (µg/L) up to 3.9 µg/L.
Understanding these detections is key: the reporting level indicates the smallest concentration measurable by the EPA's instruments, and detection above that level is simply a confirmed measurement, not an indicator of unsafe water. The total chromium maximum contaminant level (MCL) set by EPA is 100 µg/L, far higher than any measured concentration in this system. Consequently, residents can be assured no regulatory standard for safety has been exceeded.
If You Are Comparing Aesthetic Secondary Standards with Health-Based Limits
Chromium in water can contribute not only to health considerations but also to taste, staining, or corrosivity concerns, which fall under aesthetic secondary standards rather than enforceable health limits. These secondary standards guide water providers to maintain water qualities that avoid unpleasant appearance or damage to plumbing and appliances. However, these are advisory and do not signify health risks if exceeded.
The Fort Defiance/Window Rock/St. Michaels system’s chromium-6 levels, recorded as highest at 3.9 µg/L, are well below total chromium MCLs and do not invoke mandatory responses. Nonetheless, some homeowners might notice subtle effects related to taste or surface residues that motivate further water quality evaluation.
If You Want to Understand the Measured Range and Median Values
The EPA data shows chromium-6 detected in 13 out of 20 samples, with a median detected value of 0.26 µg/L. Total chromium detections occurred in 11 samples, with a median of 0.4 µg/L, both well within federal safety bounds.
For a household, these values mean the system’s water occasionally contains measurable chromium-6 but at concentrations well below the total chromium limit defined for safety. A median value represents the midpoint of detections, giving a sense of central tendency rather than maximum levels experienced. These figures do not indicate the exact concentration at an individual tap, which depends on local plumbing and specific sampling.
If You Are Considering Water Treatment and Its Maintenance
The documented approach to reducing chromium-6 levels involves the C-Series Chromium-6 Filter, designed for residential water treatment needs. This system ships ready to configure without requiring professional setup, giving homeowners control over managing their water quality.
The filter typically follows a maintenance cycle based on water usage and contaminant load, with periodic replacement or regeneration scheduled according to the manufacturer’s guidelines. Regular attention ensures continued performance in reducing chromium-6 to lower levels within household water supply lines.
If You Wonder What Happens When Chromium-6 Is Left Untreated in Household Water
Chromium-6 is a form of chromium that occurs naturally and through industrial activities. While this regional system has no health-based violations, homeowners who detect chromium-6 or experience related issues may seek treatment to address taste, staining, or personal concerns.
Leaving chromium-6 untreated does not guarantee harm given the low recorded concentrations in the regional supply, but persistent presence can sometimes contribute to water quality issues over time. Treatment systems like the C-Series Chromium-6 Filter offer an option to manage these concerns proactively, tailored to the volume of water used daily by the household.
To ensure the filter meets your household needs, consider your typical daily water use and test your own well or tap water to confirm chromium-6 levels. This informed approach supports effective, confidence-based water management aligned with your local water system’s documented data.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2015-04-01. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Fort Defiance/Window Rock/St. Michaels - NTUA (NN0403000), NN: 40 results across 2 listed contaminants, 24 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L