Copper in Drinking Water
Copper is a metal that occurs naturally and is used to make many products, including parts for plumbing systems. Copper can get into your drinking water as the water passes through your household plumbing system. Your body needs some copper to stay healthy, but too much is harmful.
Drinking water with more than 1,300 micrograms of copper per liter of water (µg/L)* can be a health risk for everyone. Infants and people with Wilson’s disease may need water with an even lower level of copper to stay safe.
Copper can get into your drinking water as it passes through your plumbing system. Over time, plumbing parts with copper in them usually build up a natural coating that prevents copper from being dissolved into the water. Plumbing systems with copper parts fewer than three years old usually have not had time to build up this protective coating. You can take the steps below to help keep your drinking water safe:
- Let the water run for at least 30-60 seconds before using it for drinking or cooking if the water has not been turned on in over six hours.
- Use cold water for drinking, making food, and making baby formula. Hot water releases more copper from pipes than cold water.
- Test your water. In most cases, letting the water run and using cold water for drinking and cooking should keep copper levels low in your drinking water. If you are still concerned about copper, arrange with a laboratory to test your tap water. Testing your water is important if an infant or someone with Wilson's disease drinks your tap water. All testing should be done through an accredited laboratory. Contact a Minnesota Department of Health (MDH) accredited laboratory to get a sample container and instructions on how to submit a sample. You can also contact your county to see if they have any programs to make testing your water easier.
- If tests show you have levels of copper over 1,300 µg/L in your tap water after you let the water run 30-60 seconds, you may want to consider treating your water. You can learn more about water treatment options at Home Water Treatment Units: Point-of-Use Devices. Contact MDH (651-201-4700 or email@example.com) with questions.
* One microgram per liter (µg/L) is the same as 1 part per billion.
If you have a private wellCopper is not usually found in the groundwater that feeds your well. Copper may enter your drinking water as it travels through your plumbing system. If your plumbing system has parts made with copper, follow the steps above to help keep your drinking water safe.
If you are on a public water system
The U.S. Environmental Protection Agency (EPA) has an action level of 1,300 µg/L for public water systems serving places where people live, work, go to school, and receive childcare. These systems have to take actions to reduce the amount of copper in the water if more than 10 percent of the water samples they take from homes and sampling sites served by the system have copper levels over 1,300 µg/L.
You can find the level of copper detected in a community water system (systems serving where you live) by reading the system’s Water Quality Report (also known as a Consumer Confidence Report [CCR]). You can call your community water system to get a copy of your CCR, or you may be able to find it online at Find Your Local CCR. Remember that your home may have higher levels of copper in drinking water than the homes your public water system tested. Follow the steps above to help keep your drinking water safe.
Noncommunity water systems serving schools, offices, factories, and childcare facilities test for copper; you can contact your noncommunity system to find the level of copper detected in the system. Noncommunity systems serving restaurants, resorts, and campgrounds are not required to test for copper.
Although the pH of groundwater in Minnesota is normally high enough to prevent water from dissolving copper, there are other water qualities that may contribute to corrosion. Public water systems monitor how corrosive water is to reduce the risk of lead and copper getting into drinking water. Learn more about copper and lead levels in Minnesota public water systems at Drinking Water Protection Annual Reports.
In 1999, the Minnesota Pollution Control Agency found that none of the 954 wells they tested in Minnesota had copper levels over the EPA action level (see Copper, Chromium, Nickel and Zinc in Minnesota’s Ground Water).
MDH regulates public water systems by:
- Approving public water systems’ treatment plans
- Enforcing the Safe Drinking Water Act, which has a specific part addressing lead and copper
- Testing public water systems
MDH also studies the presence and risk of chemicals, such as Copper Sulfate and Chromated Copper Arsenate, that break down into copper and can enter water.
- The Agency for Toxic Substances and Disease Registry provides a Toxicological Profile for Copper.
- A new U.S. Geological Survey Study Shows High Potential for Groundwater to be Corrosive in Half of U.S. States.