Bright Green/Blue Residue In Fridge Water Pipe

[rbritt]

Hi all,
I have a plumbing mystery and I'd really appreciate some theories as to what's going on!

I've installed a new fridge and on removing the water supply for it noticed a lot of green/blue deposits coming through from the pipe that fed it.

This has come out of the cold water copper pipe that feeds the fridge's water dispenser.

Previously when I've been changing the old fridge's water filter I'd noticed bright green/blue deposits in it, so I suspect this problem has been brewing for a long time.

I turned the water back on and it flushed out a lot more of it, and it was dissolved in the water too:

I had to change the isolation valve at the bottom of the pipe. It had some residue and signs of corrosion where the valve met the pipe.

Here you can see the inside of the valve and the small section of pipe I cut. Some of the deposits is almost like small chunks.

The pipe itself is painted but where it is exposed it looks fine - no sign of corrosion on the outside. The paint is smooth on it too, no sign of bubbling etc.

I have not noticed any reside in any of the other cold water taps or toilet cisterns around the house. With the amount in this pipe I would have thought it would be obvious if it was in others, like seeing residue in the sink or toilet cistern etc.

We didn't use the water dispenser on the old fridge much at all, but it did have an ice cube maker in constant use so it would have been having some water flow.

Any ideas?

 

[Wirdy]

This is the product of copper corrosion and is sometimes seen with low-use pipes, as you say the water dispenser wasn't often used. If the pipe is routed past any warm areas at the rear of the fridge it also increases the corrosion rate. The proper solution is to replace the corroded pipework & make sure you use the dispenser more in the future, or even not connect it up at all. If left as it is the fridge water may well have a metallic taste and although unlikely to cause any lasting harm to adults, it's definitely not good idea for children to drink it.

 

[rbritt]

Thanks for the reply. I'll take your advice, change the pipe and make sure we're drawing water from it more.

 

[rpm]

And remove the PTFE tape from where it has no right to be.