Chlorine and failing copper hot-water cylinders.

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JessieB

37 posts

Geek

#240962 4-Oct-2018 08:32

This is in the headlines for Christchurch. A university report has found a direct link with the recent introduction of chlorine to drinking water. However I am rather puzzled by this. From basic chemistry, does chlorine react with copper metal? Could it be that the chlorine is reacting with impurities in the metal? If so then could it be that the copper that is used in our building industry is sub-standard? Do we have standards?

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243 posts

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#2101279 4-Oct-2018 09:02

Chlorine to blame for damaged hot water cylinders in Christchurch, new study finds - Stuff

Does not appear to explain why this is not happening in other areas that already have chlorination.

My first thought was it was just hastening the failure of old cylinders but some are quite new.

linw

2850 posts

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#2101309 4-Oct-2018 09:46

Yes, how do they explain why other chlorinated areas don't have the problem?

We are in a chlorinated area and our cylinder dates from 1974!! Yes, I sometimes worry about its age, but........

May be those old cylinders had thicker copper?

Oblivian

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#2101312 4-Oct-2018 09:51

The only thing I could come up with is some sort of electrolysis with the sudden change.

Places with chlorination, would always have had harder water go through them. But in chc its been largely pure, and then BOOM. Pool water (see litmus tests online from people near the stations when the computer still hadn't worked out the dosages) levels at the flick of a switch

MikeAqua

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#2101351 4-Oct-2018 10:17

Is the chlorine is the form of hypochlorite? That can be quite corrosive of metals.

I don't have specific experience with copper but hard on less noble metals.

Mike

sbiddle

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#2101353 4-Oct-2018 10:19

It's quite an interesting link - especially when pointed out other areas have chlorinated water as well.

In Lower Hutt chlorine was added to the water after the earthquake and has now become a permanent feature. The taste of the chlorine is a lot stronger than it is in Wellington (where it's always been chlorinated).

I spent a lot of time in Christchurch earlier this year both before and after the chlorination and to be honest didn't really notice it - it was certainly nothing like the Hutt. I happily drank tap water, whereas I simply can't stand the Hutt tap water now and use a water filter at home but do still use tap water for brushing my teeth and and so on.

In a nutshell I regard the chlorine a lot worse in the Hutt than Christchurch, and yet we're not seeing media stories about hot water cylinder failures in the Hutt, not anywhere else that has chlorine in the water (which is many parts of NZ).

sbiddle

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#2101357 4-Oct-2018 10:23

Is Christchurch water hard or soft?

Interesting to see cylinder failures as a result of hard water down there - https://www.stuff.co.nz/the-press/news/north-canterbury/99971119/no-easy-solution-to-fixing-hard-water

Gilco2

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#2101370 4-Oct-2018 10:25

Myself and 4 neighbours have just replaced our hot water cylinders. All houses built by same builder in 1993. When plumber came to ours he said "builders name" I said yes. Whoever put cylinders in uses galvanised steel fittings in copper cylinders. So setup for electrolysis there plus chlorine in water didnt help. Just surprised they lasted that long.

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linw

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#2101373 4-Oct-2018 10:35

Our water in Plimmerton is soft.

Oblivian

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#2101375 4-Oct-2018 10:37

MikeAqua:

Is the chlorine is the form of hypochlorite? That can be quite corrosive of metals.

I don't have specific experience with copper but hard on less noble metals.

Affirmative.

Sodium hypochlorite is used in Christchurch. It can be added as a precaution after routine work, such as reservoir cleaning, or as a result of finding bacteria in the water supply during routine water sampling.

https://ccc.govt.nz/services/water-and-drainage/water-supply/water-chlorination/#10/-43.6102/172.7066

Big ol tanks of it electronically introduced

nitro

658 posts

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#2101447 4-Oct-2018 11:50

sbiddle:

It's quite an interesting link - especially when pointed out other areas have chlorinated water as well.

In Lower Hutt chlorine was added to the water after the earthquake and has now become a permanent feature. The taste of the chlorine is a lot stronger than it is in Wellington (where it's always been chlorinated).

I spent a lot of time in Christchurch earlier this year both before and after the chlorination and to be honest didn't really notice it - it was certainly nothing like the Hutt. I happily drank tap water, whereas I simply can't stand the Hutt tap water now and use a water filter at home but do still use tap water for brushing my teeth and and so on.

In a nutshell I regard the chlorine a lot worse in the Hutt than Christchurch, and yet we're not seeing media stories about hot water cylinder failures in the Hutt, not anywhere else that has chlorine in the water (which is many parts of NZ).

agree with your observation regarding water taste in lower hutt vs wellington.

i live in wellington and work in lower hutt. i'm happy drinking tap water at home, but can't take it when at work (we had about a week where the water dispenser, going through a filter was out of action and needed to be replaced).

itxtme

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#2101450 4-Oct-2018 11:51

In LH we have two jugs in the fridge. I cant taste the cholrine when its cold, but agree from tap its bad - especially in summer

Oblivian

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#2101458 4-Oct-2018 12:00

itxtme:
In LH we have two jugs in the fridge. I cant taste the cholrine when its cold, but agree from tap its bad - especially in summer

Many here resorted to that. And of course plumbers made a rort of it and did huge filter sales.

Closer to the station/more consumed the less time to dissipate.

You have to consider the reason cantabs are looking like/are moaning was we were use to water as good as is in those pure water bottles corporates make millions from. And people in Australia etc take for granted. Then all of a sudden have a change like going to a pool and showering. It's not uncommon for those who travel out of town (myself included) to forget how good we have(had) it until you showered or cleaned teeth with water in welly/akl. Very very noticeable in regards going from none, to even very little that other locals are accustomed to

Fred99

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#2101461 4-Oct-2018 12:07

sbiddle:

Is Christchurch water hard or soft?

Interesting to see cylinder failures as a result of hard water down there - https://www.stuff.co.nz/the-press/news/north-canterbury/99971119/no-easy-solution-to-fixing-hard-water

Main town supply in Chch is at the soft end of average - but there's some variation between bores - some are harder than others.

Not sure why Leithfield (North of Chch) is so much harder - could be that it's going through limestone deposits in N Cant'y.

raytaylor

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#2102455 6-Oct-2018 10:51

https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11985577

I think he is right - lime scale was blocking up existing leaks. Chlorine comes along and clears the lime scale and mineral build up and exposes the leak.

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Bung

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#2102468 6-Oct-2018 12:04

I don't know if it is lime scale but apparently it is related to the sediment in the bottom of the tank. Maybe there's something in Canterbury that differs from other regions.

Edit. Since 2016 the water at Foxton has been treated to reduce limescale build up in the pipes. So far my 1969 copper tank hasn't fallen apart. Fingers crossed.

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