Copper in Drinking Water

Copper is an essential nutrient that your body needs in small amounts, but when levels in drinking water get too high, it becomes a health hazard. Like lead, copper enters your water primarily through corrosion of household plumbing. Copper pipes, fittings, and fixtures are extremely common in homes built from the 1960s through the present day. When water is naturally acidic or soft (low in minerals), or when it sits in copper pipes for extended periods, the metal dissolves into the water. You may notice a blue-green stain on sinks or a metallic taste -- both are signs of elevated copper.

Short-term exposure to high copper levels causes nausea, vomiting, diarrhea, and stomach cramps. These effects can occur within hours of drinking water with copper levels significantly above the action level. Long-term exposure to moderately elevated copper levels is more insidious, potentially leading to liver damage and kidney disease. People with Wilson's disease, a rare genetic condition that impairs the body's ability to process copper, are at particular risk and should take extra precautions.

The EPA regulates copper through the Lead and Copper Rule, which requires utilities to test water at customer taps. If more than 10% of tap water samples exceed the action level of 1.3 mg/L, the water system must take steps to control corrosion. However, because copper contamination happens in your home's plumbing -- not at the treatment plant -- your individual water may test higher or lower than utility-reported averages. Testing your own tap water is the only way to know your actual exposure.