Government sampling records for the Columbus public water system, which serves over 1.3 million people through nearly 290,000 connections in Franklin County, OH, show that chromium-6, also called hexavalent chromium or chromium(VI), was detected in 20 out of 20 samples taken between 2014 and 2015. These results ranged up to 0.35 micrograms per liter (µg/L), or parts per billion (ppb), with a median of 0.195 µg/L. It is important to note that no federal maximum contaminant level (MCL) exists currently for chromium-6, and these detections are not violations or health-based exceedances.
1. Why California set its own 10 µg/L limit and what that history means for a reader elsewhere
The state of California established a regulatory limit of 10 micrograms per liter for chromium-6 in drinking water, based on health risk assessments conducted locally. This standard reflects California's precautionary approach but is not a federal mandate and does not apply to water systems outside that state, such as Franklin County. The absence of a federal MCL for chromium-6 means that public water systems nationwide must report detection levels but are not legally required to meet a chromium-6 concentration limit. While the concentrations measured in Franklin County are well below California’s limit, considering such benchmarks can inform a household’s concerns.
2. The role of plumbing material and age, separate from the source water
The levels of chromium-6 detected in a public water system sample pertain to the system’s source water and treatment processes, not directly to an individual home’s water quality. Residential plumbing materials and the age of pipes can influence chromium presence independently of the raw or treated water delivered to the property. Older plumbing or certain metal fittings may contribute trace metals, which means a home water test is the only way to determine the actual chromium-6 concentration at the tap.
3. Geogenic hexavalent chromium in arid and alkaline aquifers versus industrial plating sources
Chromium-6 in water often originates from natural geological sources (geogenic), especially in arid or alkaline aquifers where chromium-bearing minerals dissolve. Alternatively, industrial activities such as metal plating can introduce chromium-6. The Columbus water system sources its supply from surface water, which typically dilutes such constituents but can nonetheless reflect runoff or environmental deposits. Understanding the likely origin of chromium-6 in your area aids in evaluating treatment needs.
4. How sample depth, well depth or source type changes what a reader should expect
Sampling depth and the type of water source impact chromium-6 levels. Surface waters, like those supplying Columbus, usually differ in chemistry from groundwater wells, which can have higher mineral content or different contaminant profiles. For private well owners in Franklin County considering their chromium-6 risk, the depth and location of their well will affect the possibility of elevated chromium-6, emphasizing the value of individual testing rather than relying solely on public water results.
5. What the reader should write down before asking anyone for treatment advice
- Document recent water quality test results from your specific tap water or well, including chromium-6 concentration if available.
- Note your water source type (municipal surface water or private groundwater well).
- Record the age and materials of household plumbing and any existing filtration devices.
- List any known water issues such as discoloration or metallic taste that may relate to chromium-6 or other metals.
Having these details at hand will help water treatment providers or specialists offer advice tailored to your unique circumstances.
6. What happens when this problem is left untreated for years, stated without exaggeration
Long-term exposure to chromium-6 at varying levels is a subject of ongoing scientific study. The presence of chromium-6 in drinking water at low levels measured in Franklin County does not automatically indicate health risk; however, awareness and monitoring are prudent. Untreated chromium-6 retaining in water can contribute to discoloration or taste changes over time, and some consumers choose to address it for peace of mind. Any concerns about prolonged exposure should be discussed with a qualified water quality professional and health experts.
To address chromium-6, the C-Series Chromium-6 Filter ships ready to configure for household water systems and uses proven technology targeting chromium(VI). It can be a part of an overall solution after confirming the specific water chemistry in your home.
These findings and notes reflect the Columbus public water system record for Franklin County, OH, as per EPA unregulated contaminant monitoring data. For the original data and further information, visit the EPA’s website on the Unregulated Contaminant Monitoring Rule.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2014-12-16. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR3 monitoring (2013-2015) for Columbus (OH2504412), OH: 40 results across 2 listed contaminants, 37 detections above the reporting level; no federal MCL for hexavalent chromium; total chromium MCL 100 ug/L