Roberts household to CCC 30.11.15

Cashmere family asks questions of council


30 November 2015

The Manager
City Water & Waste Unit
Christchurch City Council
PO Box 73014
Orchard Road Mail Centre

Dear Sir/Madam


I have recently been advised that the water in the Cashmere area (specifically Hackthorne Road in my case) contains impurities that (amongst other effects) causes standard Hot Water Cylinder (HWC) elements to fail prematurely.


I had a new locally-made Peter Cocks Ltd mains-pressure stainless-steel HWC installed in September 2011.

In January this year the Eutron main element burst through its outer casing because of corrosion and/or build-up of impurities. It was only 16 months old! It was replaced with a similar Hermatic element. Although the original Eutron element had a warranty, the guarantee expressly excludes failure due to impurities in the water supply. I therefore had to pay the cost of the plumber and electrician, plus the element, totalling $430-35.
The replacement Hermatic element was installed. It also has a warranty, which states that it does not cover failures “due to corrosion, liming or build-up of water impurities…”.

In September this year (i.e. after only another 8 months) the Hermatic element failed in a similar way.
I decided to ring Peter Cocks Ltd (spoke to ‘Simon’) to see what type of replacement element they recommended. He said that they obviously have no idea where their HWC are installed (they are distributed through merchants). However, in the past 6 months or so they had become aware that the water in the Cashmere area contained substances that lead to premature failure of HWC elements. He suggested we have a stainless-steel element installed.
I also rang Hermatic (spoke to ‘Allan’). He recommended their ‘Incoloy’ element be used.
So a coated ‘Incoloy’ element has been installed at a cost to me of another $735-71! This cost included the replacement of the thermostat and a meter-box fuse as well because they had been damaged by the high fault-current generated when the element failed/burst.


The cost to me of the failure of the two elements, thermostat and fuse has so far been $1166-06! If the standard second booster-element (which has been used each time the main element has failed) also fails, I will incur further cost.
These costs appear to have been caused by corrosive and/or excessive liming impurities in our Council-provided local water supply.

Your Response?

I therefore have some questions that I would be grateful if you could answer, as follows:

1. Do you carry out regular tests of the composition of our local water supply? (I realise that your website provides ‘typical average chemical analysis’, but it seems that our local supply is NOT typical).

2. Can you please provide me with the most recent analysis?

3. Has the composition of the water changed significantly over recent time?

4. What financial contribution are you prepared to make towards the costs ($1166) I have incurred to date through no fault on my part or that of the HWC or element maker?

5. What steps, if any, do you propose to take to improve the quality of our local supply to hopefully prevent such premature failure?

6. Will you be informing the local residents, and Christchurch plumbers and electricians, of the current impurity problem with our local water supply, so that they can know and install special corrosion-resistant elements in our area? (From information provided by Peter Cocks Ltd, other Cashmere properties have been similarly affected).

I would appreciate your responses as soon as possible.

Thank you.

Yours sincerely


Copy to
Cashmere Residents Association (Inc)
Peter Cocks Ltd

See the CCC response here:

Is Christchurch water ok?

What’s up with Christchurch water? – for supplier resolution

Kia ora koutou,

We have been asked: what’s up with Christchurch water?

Hot-water cylinders are regularly damaged and expensive to repair, so this website collates the facts towards resolution by suppliers of water and cylinders.

‘Happy reading’ – we hope you find the shared information useful.

Waimarie ~ peaceful waters

The Editor
Christchurch Water
Cashmere Residents’ Association