Blue water and copper corrosion

Copper water pipes are sometimes affected by copper corrosion, which means that copper by-products are released into the water. If you do not use the water in a pipe that is affected by copper corrosion, the concentration of copper in the water can increase to levels that cause staining or a metallic taste.

What are the signs of copper corrosion?

If there is blue-green water or bluish cloudy water coming out of one or more cold taps in your house, you may have copper corrosion in your pipes. You will usually notice this the first time the tap is used after several days of little or no use.

There may also be a build-up of crystals or blue stains on basins or the back of the toilet bowl, or the water may have a metallic or bitter taste. In some cases the corrosion will be noticeable from pinhole leaks in the plumbing.

What causes blue water?

The cause of blue water is not completely clear. Research has found that corrosion can occur in various types of copper pipes that are old and new. Blue water does appear to be more common in pipes which have been left still for a long time or that are not regularly used. However, copper corrosion seems to be more common in soft water, such as the water in the ACT and eastern Australian states.

Why is blue water a problem?

Apart from causing the water to stain basins and toilets and possibly have a metallic taste, copper corrosion can lead to pinhole leaks in plumbing. Severe copper corrosion can also increase copper concentrations in drinking water to levels that may affect health, both in the short term and long term.

How much copper is unhealthy?

Trace amounts of copper in the diet is essential for good health. The typical daily adult requirement of copper is 2 mg to 3 mg. Most people will get the required amount through their diet, with drinking water making up a small part of this. These guidelines are based on knowledge and research to date.

There are two recommended guideline values for copper in drinking water, as contained in the Australian Drinking Water Guidelines published by the National Health and Medical Research Council, and referred to in the ACT Drinking Water Quality Code of Practice 2000 (34K — PDF).

The value based on the potential for staining fittings is set at 1 mg of copper per litre of water. The health-related guideline of 2 mg of copper per litre of water is based on a healthy person being able to drink the water everyday over a lifetime with no ill effects. Those that may be more susceptible to higher copper levels include infants, the elderly, and those suffering liver-function problems.

ActewAGL strives to provide water that meets these water quality guidelines. Our commitment to this objective is demonstrated in our monthly performance reports. Regular testing by ActewAGL has shown that Canberra's drinking water typically contains less than 0.1 mg of copper per litre of water.

What should I do if I suspect copper corrosion?

Although the cause of copper corrosion is somewhat unclear, localised copper corrosion inside the home can increase levels of copper in the water, raising concern for aesthetic or health reasons.

An increase in the concentration of copper is more likely to arise in sections of residential pipes where the water has remained unused for a period of time. It is a localised problem, which can occur in a tap that is rarely used, while other pipes within the home remain unaffected.

Where you suspect that some water pipes may be affected by copper corrosion, there are some simple steps you can take. Before using water for drinking or food preparation, run the tap for approximately one minute to flush the system. In most cases, the copper levels in the water taken after running the tap will be within the Australian Drinking Water Quality Guidelines. Regularly turning on outside taps that promote the flow of water through your household plumbing may also reduce the problem. In some cases you may need to consider replacing the affected piece of pipe.

As part of its commitment to promoting water quality, ActewAGL is happy to assist customers in determining whether copper corrosion in pipes has occurred. For advice on dealing with copper corrosion, or to arrange an inspection and water quality test, contact ActewAGL on 13 14 93. The concentration of copper in the water can then be assessed against the recommended guideline values in the Australian Drinking Water Guidelines.