Chlorine suspected in Christchurch hot water cylinder failures

As per a previous post, we are still having a disproportionate amount of cylinders blowing in properties. A retired scientist took the time to email us and explain that the hard water extracted from the ground in Christchurch has not been kind to particular kinds of copper, especially some sourced from Australia. Copper, especially when heated becomes an excellent conductor of any issues within and, ( without getting as technical as he did,) results in pitting at the joins which, in turn, results in tiny pin-holes at the seals. These pin-holes are blocked by any kind of sediment which settles in the tank in these tight sealed areas, but when something like chlorine swirls through it cleans out the sealed areas and any 'gunk' so that the holes are then free to leak. Isn't it a pity the Health Department couldn't do the same for Cholesterol?

All up, it affects those cylinders that probably would've gone long before now, but not all at the same time.

Click here to read the full article on