Hastings council says copper hot water cylinder replacement cost remains residents’ responsibility

Homeowners will continue to have to pay out of pocket to replace low-pressure copper hot water cylinders that had failed due to Hastings' unique water conditions. Photo / NZME

Hastings District Council has stood by its decision to make homeowners pay to upgrade their failing copper hot water cylinders a year on from an independent investigation that found adding chemicals to the water supply would be more equitable.

Low-pressure copper hot water cylinders (LPCU) were three years ago about 20 times more likely to fail in Hastings than in the rest of New Zealand- one-third of all failures in the country occurred in two Hastings urban postcodes from 2021-22.

An independent investigation from Stantec Consulting, commissioned by the council, found water from Hastings’ Frimley and Wilson bores had lower alkalinity and low dissolved organic carbon characteristics, which are associated with a propensity for copper pitting.

While not the sole cause, as Hastings does not chlorinate more than other NZ towns, chlorination was “very likely an important compounding factor” in the copper pitting seen on the cylinders.

Certain hot-water cylinder manufacturers have excluded Hastings from copper hot-water cylinder warranties since 2022, but homeowners were still expected to cover the installation and electrical costs of the vitreous enamel or stainless steel alternatives more resilient to Hastings’ water conditions even if they were under warranty.

The report recommended the council add phosphoric acid or sodium silicate - both found in many food and beverage products - to the water to help form a protective coating on copper components in the water network to prevent rapid corrosion.

Phosphates are commonly used in corrosion control for water across Australia, the UK, the US and Canada.

A Hastings District Council spokesperson said the council was not currently considering trialling the addition of a chemical additive to the water supply and there were no plans to consult the community about a response to the failures at this time.

“Council has maintained its position to support the manufacturers’ recommendations to replace failed products with a product suitable for local conditions,” the spokesperson said.

“An update on the status of the issue and options will be discussed with council this calendar year seeking direction. Any investment into this would need to be weighed up by council among the wider council budgeting considerations in the next Annual Plan.”

The spokesperson said there had been some contact with suppliers and industry groups to try to monitor any change in the local LPCU failure rates.

“Based on information from suppliers using warranty claim information and rates of customer queries, the rates have declined but this does not necessarily reflect the full picture.”

The spokesperson said there were unfortunately no options available for homeowners to mitigate the cost of replacing copper cylinders, but they could prevent repeat occurrences by following manufacturer recommendations.

Master Plumbers chief executive Greg Wallace said high rates of LPCU failures had not gone away.

He said the issue was beginning to emerge in other places where chlorination was being introduced or reintroduced, such as the Waimakariri District Council area in Canterbury, and he was concerned the financial burden would continue to be passed on to ratepayers during a cost-of-living crisis.

“My view is that the report was very clear that it was chlorination. Though we support safe drinking water, these are the unintended consequences it has on poor consumers,” Wallace said.

He said he didn’t understand why Hastings District Council wouldn’t at least trial the addition of a chemical additive as the report suggested.

“My problem is they spent the money on the independent report and there were some recommendations to mitigate in [the report]. They should at least answer the industry itself if they are going to do that.”

James Pocock joined Hawke’s Bay Today in 2021 and writes breaking news and features, with a focus on the environment, local government and post-cyclone issues in the region. He has a keen interest in finding the bigger picture in research and making it more accessible to audiences. He lives in Napier. james.pocock@nzme.co.nz