Plumbosolvency

What is Plumbosolvency?

Most drinking water in Aotearoa New Zealand is plumbosolvent. This means the water can dissolve small amounts of metals it may encounter, such as lead and copper in your plumbing fittings (like pipes and taps). This is most likely to happen when water stands for several hours, for example overnight. Drinking water with high levels of heavy metal is a health concern.

What are we doing to help prevent this?

Drinking water suppliers have a duty to ensure that the water we supply to you complies with the Water Service Regulation 2022, which sets maximum levels for metals in water. Water quality testing for plumbosolvency metals is carried out in each of our water supplies. However, drinking water suppliers are only responsible for drinking water quality up to the point of supply, which is normally the toby outside of your property.

There may be metals in the plumbing within your property such as in the taps, pipes or other fixtures, which can have an impact after the water has been supplied. Newer, better-quality fittings are likely to contain less harmful metals.

What can you do to prevent this?

Although the health risk is small, the Ministry of Health recommends that you flush a large cupful of water from your drinking tap each morning before use to remove any metals that may have dissolved from the plumbing fittings. You should also do this at other times when your tap has not been used for a while, like when you come back from holiday.

All households are advised to take this precaution, whether they are on public or private water supply. Other places – including commercial businesses, community buildings, and schools – should also have systems in place to ensure that drinking water taps are regularly flushed, particularly after periods of not using them like after the weekend and school holidays.