Copper pipes in the water distribution system are widely used all over the world. Corrosion of the pipes causes elevated copper levels in the drinking water. The corrosion depends on the water composition and the stagnation time of the water in the pipes. Low pH is a main factor determining the release of copper, and high alkalinity is also an important contributing factor, especially at a low pH. This is in contrast to corrosion of iron pipes, which is prevented by increasing the alkalinity. Copper in drinking water may contribute significantly to the dietary intake of copper, and sometimes drinking water is the major source. However, it is difficult to calculate the intake of copper from drinking water, as the concentrations can vary one or two orders of magnitude, depending on the flushing habits. Gastrointestinal effects (e.g., nausea, vomiting, diarrhea, and abdominal pains) have been reported after exposure to high concentrations of copper in drinking water. Owing to lack of data, the tolerated level of copper in water can not be firmly established, but guideline values of 1-2 mg/L have been recommended. A higher sensitivity in newborns to elevated copper exposure has been suggested. Release of copper from the pipes will also result in elevated copper concentrations in waste-water sludge and may limit the use of sludge for agricultural purposes. The critical concentration at which copper must be considered from ecotoxicological aspects depend on the biota and exposure conditions at the actual site. Major effects due to elevated copper concentrations in the environment includes decreased growth of plants, disturbed reproduction in several species of invertebrates, and copper poisoning in livestock and fish. Aquatic organisms, especially certain species of crustaceans, have the highest sensitivity to copper toxicity. Effects on fish can be significant already at levels below 0.01 mg/L. The consequences of the extensive and widespread environmental pollution of copper from the intentional use of copper as piping material need to be investigated and thoroughly evaluated.Key words: copper, drinking water, plumbing, health effects, toxicity, sewage sludge.