27 Jul 2024

Unravelling the Hastings Hot Water Cylinder Mystery


The mystery surrounding the alarming rate of hot-water cylinder failures in Hastings, New Zealand, has finally been solved. A new report, commissioned by the council and conducted by Stantec Consulting, sheds light on the root cause of the issue.

The data collected from plumbers and hot-water cylinder manufacturers revealed a shocking statistic: low-pressure copper hot-water cylinders (LPCUs) in Hastings were about 20 times more likely to fail than those in other parts of the country. Two major hot-water cylinder manufacturers had even excluded Hastings from their warranties, citing "localised water conditions" as the reason.



The investigation focused on chlorination, as it was initially thought to be a potential cause of the copper pitting seen on the cylinders. Surprisingly, the report found that while chlorination was a compounding factor, it wasn't the sole reason for the higher failure rates in Hastings compared to other areas with chlorinated water.

The key finding was that water from the Frimley and Wilson bores in Hastings had lower alkalinity and low dissolved organic carbon characteristics, which made them more prone to copper pitting. This unique water chemistry in Hastings explained the disproportionately high number of hot-water cylinder failures.

To address this issue, the report recommended a chemical solution which has been successfully used in corrosion control for water in various countries worldwide. However implementing the chemical solution comes with financial implications. Homeowners, as well as the council, would need to consider the costs involved. While the financial burden is a concern, it is also essential to prioritise the safety of the drinking water, as chlorine addition is mandatory according to New Zealand's drinking water regulator, Taumata Arowai.

The benefit of the chemical solution approach is that it offers an equitable and efficient solution for the entire system in a few months. On the other hand, the non-treatment approach is to gradually replace copper-based plumbing and hot-water cylinder components, however this is dependent on homeowners' actions and will take a long time.


If you're a homeowner located in Hastings contact our team for free advice.


Contact Us     Call Us 0800 234 800