Flush Your Taps

Research carried out by the Institute of Environmental Science and the Ministry of Health has shown that some New Zealand water supplies contain minute traces of lead that are near to or exceed the maximum acceptable level specified in the New Zealand Drinking Water Standards. Traces of metals – in particular lead – are of concern because over time they pose a potential health risk, especially if consumed from childhood.

It is important to note that the lead is not coming from the water supplies themselves, but primarily from metals in some household fittings that may be dissolved into the water. The amount of lead that will dissolve from a fitting depends on how plumbosolvent* the water is; the temperature of the water; the composition of the plumbing fittings and how long the water has been in contact with it.

The fact that most New Zealand waters are of very good quality and contain little dissolved substances such as calcium and magnesium salts contributes to their plumbosolvency, which is widespread in New Zealand. The Ministry of Health therefore recommends that people do not drink the first mugful of water if their tap has not been used for several hours overnight, for instance.

Instead, people should run the tap for a second or so, which will quickly flush-away any water that has become contaminated with lead or any other metals from the plumbing fittings. The Ministry of Health works closely with Standards New Zealand and the plumbing industry to develop quality standards for plumbing fittings.

Additional details on this issue can be sourced from the Ministry of Health website – www.moh.govt.nz.

* plumbsolvent = The types of water that have the ability to dissolve lead (usually soft waters) are known as ‘plumbsolvent’ because of their ability to dissolve lead (from the Latin word plumbum).