Copper in Drinking Water

Copper is a naturally occurring element in soil, sediment, rock and water, and it is naturally present in small concentrations in rivers and groundwater. However, most elevated concentrations of copper in drinking water are due to corrosion of copper pipes. Corrosion of copper pipes is associated with acidic or soft water, high levels of residual chlorine, long standing-time of water in pipes, and hot water.

Copper continues to dissolve as water sits in copper pipes, so water that has been sitting for a long time in copper pipes may have elevated concentrations of copper. Homes with newer copper pipes may be particularly susceptible because protective coatings may not have had time to form on the inside of the pipes.

If elevated levels of copper are present in the water, the copper can be cleared from the lines by running the water from the tap for 30 to 60 seconds before using it for drinking or cooking. Because hot water dissolves copper faster, water from the hot water tap should not be used for cooking or drinking. Baby formula should especially never be made using hot water from the tap.

At copper concentrations above 1 milligrams per liter (mg/L or ppm), it can cause staining of laundry and dishes. At 2.5 milligrams per liter, water starts to taste bitter, and water can develop an odor at higher concentrations of copper.

Copper and Human Health

Copper is important to human health as an essential nutrient in low amounts. Menkes syndrome is one health problem that causes some people to be deficient in copper due to minimal absorption in the intestines. However, elevated concentrations of copper in drinking water can cause health problems such as vomiting, diarrhea, stomach cramps, and nausea, as well as liver and kidney problems. Children less than one year old are especially susceptible to the toxic effects of copper. A particular health condition known as Wilson’s disease makes some people have difficulty maintaining proper levels of copper in the body.

The U.S. Environmental Protection Agency (USEPA) has set a maximum contaminant level (MCL) and maximum contaminant level goal (MCLG) for copper of 1.3 milligrams per liter. A MCL is the maximum concentration of a contaminant legally allowed in public drinking water systems under the Safe Drinking Water Act. The MCLG is the level of copper in drinking water at which no adverse health risks are likely to occur, with an adequate margin of safety. However, people with Wilson’s disease may require a lower limit of copper. Detection of copper in water requires chemical testing.

How to Remove Copper from Drinking Water

Copper can be removed from drinking water by one of several different methods, including reverse osmosis, distillation, and ion exchange filtering. Reverse osmosis works by forcing water through a membrane that allows water to pass through but blocks ions such as copper. In homes, reverse osmosis systems are usually small systems (called point-of-use systems) located near the kitchen sink.

Reverse osmosis systems are cost-effective, yet they originally could only produce a small amount (a few gallons) of treated water per day.  Significant recent improvements in membrane elements allow for systems that produce 100 or more gallon per day. Taste of the water may be affected by the removal of the minerals.

Distillation systems work by removing dissolved solids from water by distillation, and small systems are available that can be placed on a kitchen counter. However, these systems are limited to producing small amounts of water per day. Also, because they use electricity to boil the water, the cost of use of distillation systems is higher than for reverse osmosis systems.

Ion exchange filters work by removing copper ions by adsorbing them onto mineral particles or resins. This takes place in filter cartridges, which may be part of point-of-use systems (near the kitchen sink) or point-of-entry systems that treat all water entering the house. These filters must be replaced periodically to maintain their effectiveness over time.

If copper is present in elevated level in the water treated by a municipality or a water company, check with them first. They are required to reduce it below EPA limits. If their testing is fine, next culprit would be copper plumbing and an acidic, low pH water. Test your water for pH , if it 6.5 or below your water is acidic and may corrode copper pipes. In order to remove copper in this case you need to add an Acid Neutralizer to balance pH.