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Published 24/02/2021

Media release: reports of ‘blue staining’ at some Featherston & Greytown properties

Wellington Water and South Wairarapa District Council have noted a recent increase in the number of reports of bathroom fixtures in Featherston & Greytown showing signs of blue staining, often around plugholes and where tap fixtures tend to drip.

Wellington Water Chief Advisor Laurence Edwards says the blue colour is an indication of 'cuprosolvency', or copper corrosion, typically seen in older homes with copper plumbing.

"Cuprosolvency can happen when water sits still in copper piping for a while, often overnight. South Wairarapa’s water, like many parts of New Zealand, is naturally slightly acidic (has a lower pH), which can exacerbate the problem. We are upgrading the systems for balancing this acidity at the Waiohine and Memorial Park water treatment plants this year, as part of our ongoing programme of capital upgrades."

Blue staining commonly occurs where taps have slow drips or leaks, often under the hot tap, so householders experiencing the issue should endeavour to fix those.

“The other important piece of advice is to flush your taps and pipes by running them for at least 500ml when you turn them on, especially first thing in the morning,” Mr Edwards says.

This is standard Ministry of Health advice, and applies to all homeowners, even when there are no signs of staining, and in properties without copper plumbing, as a simple precaution to manage the potential for plumbosolvency.

Plumbosolvency is the umbrella term used to describe the effect where water standing in taps and other fixtures has potential to leach traces of heavy metals. Water with safe levels of metals can be obtained by flushing 500ml of water from the cold tap before using the water for drinking, cooking, or brushing your teeth. Wellington Water publishes plumbosolvency information and advice every six months right across the Wellington region in newspapers and on social media, as per Ministry of Health requirements.

Regional Public Health have advised that copper leaching from household pipes is very unlikely to be a health concern, especially when taking the precaution to flush pipes.

Euan Stitt, Operations & Partnerships Manager at South Wairarapa District Council says that the number one priority for the water treatment plants serving Featherston and Greytown remains completing the upgrades that ensure all of South Wairarapa’s town water is compliant with drinking water standards and meets peak demand.

“These works are progressing well. The safety of town drinking water has already been significantly improved and full compliance with the standards is on track to be achieved later this year. Design and procurement for the upgraded pH balancing systems is already underway, and we will be working with Wellington Water to ensure they are installed and operating as soon as possible.”

Mr Stitt says the pH balancing system upgrades are currently on track to be completed by the end of May.

Since mid-January, Wellington Water has received reports of blue staining at a total of 21 properties in Featherston and Greytown out of approximately 2,600 currently serviced by the Council-owned drinking water network.

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