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Basic Information about Cadmium in Drinking Water

Cadmium at a Glance

Maximum Contaminant Level (MCL) = 0.005 milligrams per Liter (mg/L) or 5 parts per billion (ppb)

Maximum Contaminant Level Goal (MCLG) = 0.005 mg/L or 5 ppb

Health Effects
Some people who drink water containing cadmium in excess of the MCL over many years could experience kidney damage.

Drinking Water Health Advisories provide more information on health effects

Chemical Abstract Service Registry Number
7440-43-9

Sources of Contamination
Corrosion of galvanized pipes; erosion of natural deposits; discharge from metal refineries; runoff from waste batteries and paints

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

EPA regulates cadmium in drinking water to protect public health. Cadmium 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 cadmium ?
Cadmium is a metal found in natural deposits such as ores containing other elements.

Uses for cadmium.
Cadmium is used primarily for metal plating and coating operations, including transporation equipment, machinery and baking enamels, photography, and television phosphors. It is also used in nickel-cadmium solar batteries and pigments.

If you are concerned about cadmium in a private well, please visit:

What are cadmium's health effects?
Some people who drink water containing cadmium well in excess of the maximum contaminant level (MCL) for many years could experience kidney damage.

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

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What are EPA's drinking water regulations for cadmium?
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 cadmium is 0.005 mg/L or 5 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 cadmium, called a maximum contaminant level (MCL), at 0.005 mg/L or 5 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 cadmium, 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 cadmium as part of the Six Year Review and determined that the 0.005 mg/L or 5 ppb MCLG and 0.005 mg/L or 5 ppb MCL for cadmium are still protective of human health.

States may set more stringent drinking water MCLGs and MCLs for cadmium than EPA.

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How does cadmium get into my drinking water?
The major sources of cadmium in drinking water are corrosion of galvanized pipes; erosion of natural deposits; discharge from metal refineries; runoff from waste batteries and paints.

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 cadmium is in my drinking water?
When routine monitoring indicates that cadmium levels are above the MCL, your water supplier must take steps to reduce the amount of cadmium 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.

If your water comes from a household well, check with your health department or local water systems that use ground water for information on contaminants of concern in your area.

How will cadmium be removed from my drinking water?
The following treatment method(s) have proven to be effective for removing cadmium to below 0.005 mg/L or 5 ppb: coagulation/filtration, ion exchange, lime softening, reverse osmosis.

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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 and upgrade the supply of safe drinking water. Your water bill or telephone book's government listings are a good starting point for local information.

Contact your water utility. 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.

The CCR summarizes information regarding sources used (i.e., rivers, lakes, reservoirs, or aquifers), any detected contaminants, compliance and educational information.

Some water suppliers have posted their annual reports on EPA's Web site.

Other EPA Web sites

Other Federal Departments and Agencies

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