The council is reassuring the public its water supplies remain safe. Photo: RNZ / Cole Eastham-Farrelly
South Wairarapa's water supplies are failing to meet standards set by the new water regulator Taumata Arowai.
Meanwhile, the council wants to reassure the public its water supplies remain safe and that improvement work is underway to meet the standards.
In a report to a recent Wellington Water committee meeting, it was revealed South Wairarapa's Waiohine, Memorial Park, and Martinborough water treatment plants were not compliant with Taumata Arowai's new rules "due to insufficient treatment to meet the source water risk".
In November last year, Taumata Arowai and the Water Services Act 2021 lifted the bar on safe drinking water in New Zealand.
In response to these new regulations, Wellington Water reviewed all South Wairarapa drinking water treatment plants to see how they measured up, a South Wairarapa spokesperson said.
"At Greytown's main water source, Soldiers Memorial Park, the plant is currently non-compliant with the new regulations.
"An ultraviolet [UV] treatment unit was put in place temporarily in 2019 to provide an additional barrier to contamination, but another barrier [filtration] is required to meet the new standards.
"A project is in progress to ensure its compliance, which is planned to begin this winter and to be completed in November 2023."
The Martinborough water treatment plant has UV in place, and a manganese reduction plant and chlorination have been added in the last few years, the spokesperson said.
"However, to meet the new regulations, a further treatment barrier is needed, and a project is being initiated to upgrade the treatment plant to achieve this."
The Waiohine treatment plant that supplies Featherston - and, at times, Greytown - was the subject of a major renovation and expansion project that finished last year, making it more resilient and improving the safety of the drinking water.
"Improvements have been made to the underground Boar Bush emergency water storage tank, where it diverts to before heading to Featherston.
"Further testing and monitoring of the source water at the Waiohine water treatment plant is expected to confirm that no further treatment is needed above what is now in place."
The council spokesperson said Wellington Water carefully monitors the water at all South Wairarapa treatment plants on an ongoing basis, and its test shows the water is safe.
"It is important to understand that compliance and water safety are two separate, but related, matters," they said.
"Compliance relates to how the water supplies stack up against the standards and regulations.
"Indeed, it is possible to have a compliant water supply that becomes unsafe due to unexpected events or changes - such as lightning strikes on machinery, flooding, etc.
"If tests show the water is unsafe, the public would be notified promptly, and actions would be taken to minimise any risk to public health."
Wellington Water has been assessing the impact of Taumata Arowai's new rules for the Pirinoa treatment plant.
This small-scale plant did not comply with the old rules but may under the new regulations.
A Masterton District Council spokesperson said the district's water supply was "fully compliant".
In Carterton, meanwhile, full compliance was achieved in January after running into data gap issues at the Frederick St Water Treatment Plant in November and December.
"Under the old standards, our network was considered non-compliant due to gaps in data being unable to demonstrate compliance. This was included in our most recent annual report," a council spokesperson said.
A project to upgrade the Frederick St bore and treatment plant will help the council towards sustainable compliance "and provide us with up-to-the-minute data as required by legislation", the spokesperson said.
"This project is close to completion, and we look forward to the benefits it will provide the community."
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