Testing Laboratory, Inc.
|Copper in Drinking Water
| Copper is a reddish metal that occurs naturally in rock, soil, water, sediment, and air. Its unique
chemical and physical properties have made it one of the most commercially important metals. Since
copper is easily shaped or molded, it is commonly used to make pennies, electrical wiring, and water pipes.
Copper compounds are also used as an agricultural pesticide, and to control algae in lakes and reservoirs.
Copper and its compounds are common in the environment. You may be exposed to copper by breathing
air, eating food, or drinking water containing copper. You may also be exposed by skin contact with soil,
water, or other copper-containing substances.
Copper forms different compounds when it joins with one or more other chemicals. These may be
naturally-occurring or man-made. Most copper compounds found in air, soil, and water are strongly
attached to dust or embedded in minerals, and cannot easily enter the body. These forms are not likely
to affect your health. Other forms become dissolved in water and are not attached to other particles.
In this form, copper is more likely to affect your health.
Levels of copper found naturally in ground water and surface water are generally very low; about 4
micrograms of copper in one liter of water (4 ug/L) or less. However, drinking water may contain higher
levels of a dissolved form of copper.
High levels of copper occur if corrosive water comes in contact with copper plumbing and copper-containing
fixtures in the water distribution system. If corrosive water remains motionless in the plumbing system
for six hours or more, copper levels may exceed 1,000 ug/L. The level of copper in drinking water
increases with the corrosivity of the water and the length of time it remains in contact with the plumbing.
Copper in our diet is necessary for good health. You eat and drink about 1,000 micrograms (1,000 ug)
of copper per day. Drinking water normally contributes approximately 150 ug/day. Immediate effects
from drinking water which contains elevated levels of copper include
The seriousness of these effects can be expected to increase with increased copper levels or length of
Children under one year of age are more sensitive to copper than adults. Long-term exposure (more
than 14 days) to copper in drinking water which is much higher than 1,000 ug/L has been found to cause
kidney and liver damage in infants. Other persons who are highly susceptible to copper toxicity include
people with liver damage or Wilson's disease.
On the average, drinking water accounts for less than 5% of our daily copper intake. The U.S.
Environmental Protection Agency (U.S. EPA) has determined that copper levels in drinking water should not
exceed 1300 ug/l. No adverse health effects would be expected if this level is not exceeded. Measures
should be taken to reduce exposure to copper if this level is exceeded.
Because copper exhibits these harmful health effects, and because drinking water may be a significant
route of exposure to copper, it is important to know how much copper is in your drinking water. You may
find that there is a metallic taste in your drinking water before copper levels are high enough to cause
adverse health effects. You may also notice blue or bluish-green stains around sinks and plumbing
fixtures. The only way to be certain of the copper level in your drinking water supply is to have the
water tested. It is recommended that you use a laboratory that is state certified to analyze copper
levels in drinking water.