Chromium-6, also called hexavalent chromium, is a form of chromium that can occur in drinking water from both natural and industrial sources. It became widely known through the Erin Brockovich case, but chromium-6 remains a water quality topic in many communities today.
This guide explains what chromium-6 is, how it can enter drinking water, why it matters, current drinking water standards, and practical steps homeowners can take to better understand and reduce potential exposure.
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What Is Chromium-6?
Chromium is a naturally occurring element found in rocks, soil, plants, animals, and water. It can exist in different chemical forms. Two of the most discussed forms are:
- Chromium-3: Also called trivalent chromium, this form is considered an essential nutrient in very small amounts.
- Chromium-6: Also called hexavalent chromium, this form is associated with industrial uses and greater health concerns.
Chromium-6 is the form most often discussed in drinking water contamination because it can be more mobile in groundwater and is more toxic than chromium-3.
Where Does Chromium-6 Come From?
Chromium-6 can come from both natural and human-related sources. In some areas, it occurs naturally as groundwater moves through chromium-containing rocks and minerals. In other cases, chromium-6 may be linked to industrial activity.
Potential sources include:
- Natural geological formations
- Groundwater aquifers
- Metal plating operations
- Stainless steel and alloy manufacturing
- Textile production
- Leather tanning
- Wood preservation
- Industrial waste sites
- Improper chemical disposal
How Can Chromium-6 Get Into Drinking Water?
Chromium-6 may enter drinking water when it moves into groundwater or surface water used for public supplies or private wells. In areas with naturally occurring chromium, groundwater can pick up chromium-6 as it passes through local rock and soil.
In areas with industrial history, chromium-6 may enter water through spills, leaks, waste disposal, or contaminated soil and groundwater.
Can You Taste, Smell, or See Chromium-6 in Water?
No. Chromium-6 usually has no noticeable taste, odor, or color at levels found in drinking water.
Water can look clear and taste normal while still containing measurable chromium-6. Laboratory testing is the only reliable way to determine whether it is present.
Potential Health Concerns
Health concerns depend on the amount of chromium-6 present, how long exposure occurs, and individual health factors. Chromium-6 has been studied for potential effects involving the digestive system, liver, kidney, and cancer risk after long-term exposure.
Because the science continues to be reviewed, regulatory agencies may evaluate chromium-6 differently over time. Homeowners should rely on current water quality reports, certified testing, and guidance from public health agencies.
EPA Drinking Water Standard for Chromium
The U.S. Environmental Protection Agency currently regulates total chromium in public drinking water systems at 100 parts per billion, also written as 0.1 mg/L. Total chromium includes chromium-3, chromium-6, and other forms of chromium.
At the federal level, there is currently not a separate national drinking water limit specifically for chromium-6. However, the EPA continues to review chromium-6 science and health effects.
Source: EPA: Chromium in Drinking Water.
California’s Chromium-6 Drinking Water Standard
California has adopted a separate drinking water standard for hexavalent chromium. In 2024, California established a Maximum Contaminant Level of 10 parts per billion for chromium-6 in drinking water.
This state-level standard is especially relevant for California households and water systems because some regions have naturally occurring chromium-6 in groundwater.
Source: California State Water Resources Control Board: Hexavalent Chromium.
Who May Be More Likely to Have Chromium-6 in Water?
Chromium-6 can occur in different regions, but some homes may have a higher chance of exposure based on local geology, water source, and land use.
Potential higher-risk situations include:
- Homes using private wells in areas with naturally occurring chromium
- Communities relying on groundwater in regions known for chromium-6 occurrence
- Homes near industrial facilities that used chromium compounds
- Properties near metal plating, manufacturing, or waste disposal sites
- Areas with documented groundwater contamination
Should Private Well Owners Test for Chromium-6?
Yes, testing may be worthwhile if your home uses a private well, especially if you live in an area where chromium-6 has been found in groundwater.
Private well owners are generally responsible for testing and maintaining their own water quality. If chromium-6 is a concern in your region, ask a certified laboratory whether they offer testing specifically for hexavalent chromium, not just total chromium.
How Can Homeowners Reduce Chromium-6 Exposure?
If you are concerned about chromium-6 in your drinking water, consider these practical steps:
- Review your local water utility’s Consumer Confidence Report if you receive municipal water.
- Check whether your state or local water agency has chromium-6 monitoring data.
- Test private well water through a certified laboratory if appropriate.
- Ask specifically about chromium-6 testing, not only total chromium.
- Use a quality point-of-use filtration system designed to reduce a broad range of unwanted contaminants.
- Replace filter elements according to product guidance.
Berkey® Water Filters and Chromium-6 Reduction
Berkey® countertop gravity-fed water filter systems are designed for everyday household use.
When equipped with Black Berkey® Replacement Filters, Berkey® systems are designed to reduce a broad range of unwanted contaminants, including chromium-6, while leaving beneficial minerals in the water.
For most households, the Big Berkey® Water Filter offers an excellent balance of capacity, convenience, and daily countertop use.
Choosing the Right Berkey® System
| System | Capacity | Recommended For | Product |
|---|---|---|---|
| Travel Berkey® | 1.5 Gallons | Singles & Couples | View Product |
| Big Berkey® | 2.25 Gallons | Most Families | View Product |
| Royal Berkey® | 3.25 Gallons | Larger Families | View Product |
| Imperial Berkey® | 4.5 Gallons | High Daily Water Use | View Product |
| Crown Berkey® | 6 Gallons | Large Homes & Offices | View Product |
Related Drinking Water Guides
Learn more about common drinking water contaminants and filtration:
- Drinking Water Contaminants Reference Guide
- Lead in Drinking Water Guide
- PFAS in Drinking Water Guide
- Arsenic in Drinking Water Guide
- VOCs in Drinking Water Guide
- Hard Water Guide
Frequently Asked Questions
What is chromium-6?
Chromium-6, also called hexavalent chromium, is a form of chromium that can occur naturally or come from industrial activity. It is more toxic than chromium-3 and is monitored because of potential long-term health concerns.
Is chromium-6 the same as total chromium?
No. Total chromium includes multiple forms of chromium, including chromium-3 and chromium-6. Chromium-6 testing measures the hexavalent form specifically.
Can boiling water remove chromium-6?
No. Boiling water does not remove chromium-6 and may slightly concentrate minerals or metals as water evaporates.
Can I see or taste chromium-6 in water?
No. Chromium-6 usually has no noticeable taste, smell, or color at levels found in drinking water. Testing is required to know whether it is present.
Is chromium-6 regulated in drinking water?
The EPA regulates total chromium in public drinking water systems at the federal level. California has also adopted a separate drinking water standard specifically for chromium-6.
Should private well owners test for chromium-6?
Private well owners should consider testing if they live in an area with naturally occurring chromium, nearby industrial activity, or known groundwater contamination.
Which Berkey® system is best for most families?
The Big Berkey® Water Filter is the most popular choice for families because it offers a practical 2.25-gallon capacity and convenient countertop gravity-fed filtration.
Where can I buy replacement filters?
You can shop genuine replacement elements on our Berkey® Replacement Filters page.
Final Thoughts
Chromium-6 is an important drinking water topic because it can occur naturally in groundwater and may also be linked to industrial contamination. Since it cannot be detected by sight, taste, or smell, water quality reports and laboratory testing are the best ways to understand whether chromium-6 is a concern in your area.
For homeowners who want an added point-of-use filtration step, a countertop gravity-fed system can be a practical everyday option.
If you want a versatile system for daily household use, explore the Big Berkey® Water Filter.