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Water: Basic Information about Regulated Drinking Water Contaminants

Basic Information about Chromium in Drinking Water

EPA currently regulates chromium-6 as part of the total chromium drinking water standard. New health effects information has become available since the original standard was set, and EPA is reviewing this information to determine whether there are new health risks that need to be addressed. Additional information can be found at http://water.epa.gov/drink/info/chromium/index.cfm.
Chromium at a Glance

Maximum Contaminant Level (MCL) = 0.1 milligrams per Liter (mg/L) or 100 parts per billion (ppb)

Maximum Contaminant Level Goal (MCLG) = 0.1 mg/L or 100 ppb

Health Effects
Some people who drink water containing chromium (total) in excess of the MCL over many years could experience allergic
dermatitis.

Drinking Water Health Advisories provide more information on health effects

Chemical Abstract Service Registry Number
7439-92-1

Sources of Contamination
Discharge from steel and pulp mills; erosion of natural deposits

List of all Regulated Contaminants (PDF) (6 pp, 396K, About PDF)

Basic Information about Chromium in Drinking Water

Ensuring safe drinking water for all Americans is a top priority for EPA. EPA has a drinking water standard of 0.1 mg/L for total chromium, which includes chromium-6, and we require water systems to test for chromium. This standard is based on the best available science and is enforceable by law. EPA regularly re-evaluates drinking water standards and, based on new science on chromium-6, had begun a rigorous and comprehensive review of its health effects in 2008. In September 2010, we released a draft of that scientific assessment for public comment. When this human health assessment is finalized in 2011, EPA will carefully review the conclusions and consider all relevant information to determine if a new standard needs to be set.

Chromium may cause health problems if present in public or private water supplies in amounts greater than the drinking water standard set by EPA.

What is chromium (total)?
Chromium is a metallic element in the periodic table. It is odorless and tasteless. Chromium is found naturally in rocks, plants, soil and volcanic dust, humans and animals. The most common forms of chromium in the environment are trivalent (chromium-3), hexavalent (chromium-6) and the metal form, chromium-0. Chromium-3 occurs naturally in many vegetables, fruits, meats, grains and yeast. Chromium-6 and -0 are generally produced by industrial processes.

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Uses for chromium (total).
Chromium-0 is used mainly for making steel and other alloys. Chromium compounds, in either the chromium-3 or -6 forms are used for chrome plating, dyes and pigments, leather and wood preservation

If you are concerned about chromium (total) in a private well, please visit:

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What are chromium (total)'s health effects?
Chromium-3 is a nutritionally essential element in humans and is often added to vitamins as a dietary supplement. Chromium-3 has relatively low toxicity and would be a concern in drinking water only at very high levels of contamination, unlike chromium-6 and -0, which are more toxic and pose potential health risks to people. Some people who use water containing chromium (total) well in excess of the maximum contaminant level (MCL) over many years could experience allergic dermatitis.

This health effects language is not intended to catalog all possible health effects for chromium (total). Rather, it is intended to inform consumers of some of the possible health effects associated with chromium (total) in drinking water when the rule was finalized.

In a Sept 2010 draft human health assessment for chromium-6, EPA is proposing to classify chromium-6 as likely to be carcinogenic to humans via ingestion. The Agency expects to complete the health risk assessment and make a final determination about the carcinogenicity of chromium-6 in 2011.

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What are EPA's drinking water regulations for chromium (total)?
In 1974, Congress passed the Safe Drinking Water Act. This law requires EPA to determine the level of contaminants in drinking water at which no adverse health effects are likely to occur. These non-enforceable health goals, based solely on possible health risks and exposure over a lifetime with an adequate margin of safety, are called maximum contaminant level goals (MCLG). Contaminants are any physical, chemical, biological or radiological substances or matter in water.

The MCLG for chromium (total) is 0.1 mg/L or 100 ppb. EPA has set this level of protection based on the best available science to prevent potential health problems. EPA has set an enforceable regulation for chromium (total), called a maximum contaminant level (MCL), at 0.1 mg/L or 100 ppb. MCLs are set as close to the health goals as possible, considering cost, benefits and the ability of public water systems to detect and remove contaminants using suitable treatment technologies. In this case, the MCL equals the MCLG, because analytical methods or treatment technology do not pose any limitation.

The Phase II Rule, the regulation for chromium (total), became effective in 1992. The Safe Drinking Water Act requires EPA to periodically review the national primary drinking water regulation for each contaminant and revise the regulation, if appropriate. EPA reviewed chromium (total) as part of the second Six Year Review in a March 2010 (75 FR 15499). The Agency noted in its March 2010 FR that EPA had initiated a reassessment of the health risks associated with chromium exposure and determined that the 0.1 mg/L or 100 ppb MCLG and 0.1 mg/L or 100 ppb MCL for chromium (total) is still protective of human health.  When this human health assessment is finalized in 2011, EPA will carefully review the conclusions and consider all relevant information to determine if the current standard should be revised.

States may set more stringent drinking water MCLGs and MCLs for chromium (total) than EPA.

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How does chromium (total) get into my drinking water?
Major sources of chromium-6 and chromium-0 in drinking water are discharges from steel and pulp mills, and erosion of natural deposits of chromium-3. At many locations, chromium compounds have been released to the environment via leakage, poor storage, or improper disposal practices. Chromium compounds are very persistent in water as sediments. There is a high potential for accumulation of chromium in aquatic life.

A federal law called the Emergency Planning and Community Right to Know Act (EPCRA) requires facilities in certain industries, which manufacture, process, or use significant amounts of toxic chemicals, to report annually on their releases of these chemicals. For more information on the uses and releases of chemicals in your state, contact the Community Right-to-Know Hotline: (800) 424-9346.

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How will I know if chromium (total) is in my drinking water?
When routine monitoring indicates that chromium (total) levels are above the MCL, your water supplier must take steps to reduce the amount of chromium (total) so that it is below that level. Water suppliers must notify their customers as soon as practical, but no later than 30 days after the system learns of the violation. Additional actions, such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.

Citizens concerned about the safety of their drinking water can take additional steps. Consumers of public water can contact the provider to ask if their tap water contains chromium. You can find contact information for your public water system on your water bill.  Consumers served by private wells can have their water tested by a state certified laboratory. You can find one in your area by calling the Safe Drinking Water Hotline at 800-426-4791 or by contacting your state water certification officer.  Contact information for your state can be found at http://water.epa.gov/scitech/drinkingwater/labcert/statecertification.cfm.

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How will chromium (total) be removed from my drinking water?
The following treatment method(s) have proven to be effective for removing chromium (total) to below 0.1 mg/L or 100 ppb: coagulation/filtration, ion exchange, reverse osmosis, lime softening.

If a consumer is concerned about chromium in their water, then they can consider installing a home treatment unit that has been certified to remove chromium +6 (hexavalent chromium).  NSF  International  http://www.nsf.org/Certified/DWTU/ and the Water Quality Association http://www.wqa.org/sitelogic.cfm?id=1165 provide lists of treatment devices they have certified.

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How do I learn more about my drinking water?
EPA strongly encourages people to learn more about their drinking water, and to support local efforts to protect the supply of safe drinking water and upgrade the community water system. Your water bill or telephone book's government listings are a good starting point for local information.

Check your water system provider’s website or contact your water provider. EPA requires all community water systems to prepare and deliver an annual consumer confidence report (CCR) (sometimes called a water quality report) for their customers by July 1 of each year. If your water provider is not a community water system, or if you have a private water supply, request a copy from a nearby community water system.

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