Where is all the black stuff coming from?

[David WE Roberts]

....in the water, that is.

Two problems:

(1) When I run the cold mains at full blast (e.g. the bath tap) I get a few black flecks in the water. Not a massive amount, but I didn't think I should get any.

(2) When I take the head off the electric shower and run it full blast on cold, a large amount of cr*p comes out. This seems to be mainly limescale, black on one side, but there are also some coppery blue bits. I expect the very old Triton T80 shower to have some clag in as this is a very hard water area, but it just seems to keep on coming. I thought the shower has a fairly small area of heating coil and there seems to be an awful lot of stuff coming out.

We should be getting rid of the shower soon - new heating system which will run a mains pressure shower - so I'm not too worried about that. I'm more concerned about the black bits in the cold mains.

If this is from internal pipework this isn't too bad as this is also going

- ripping it all out back to the stopcock (and changing the stopcock because it doesn't stop).

If it coming in from the mains water supply I would prefer that it did not.

Is there any easy way to filter incoming cold mains without drastically reducing the pressure? I presume the filter should be easily changeable as well.

TIA

Dave R

[Andrew Gabriel]

I got the same two-coloured pieces in the hot supply from an old Main multipoint water heater. It was replaced about 5 years ago with the then current model which has an internal teflon coating on the heat exchanger pipework, and that seems to prevent scale building up in the heat exchanger, as it hasn't happened since, and it's never needed descaling.

It's probably coming from iron pipework. Do you have iron pipes either before or after the main stop c*ck?

[David WE Roberts]

I think the pipes embedded in the kitchen wall after the stopcock may well be iron. There are certainly a few bits of iron pipe around the central heating so iron may also be in the cold water supply.

If the piping before the stopcock is iron, then presumably I have to fit a new run of plastic pipe from the road, or fit some kind of filter?

Running new pipe could be a problem - the drive is block paved and the current water runs under the floor of the garage (or of the house).

What are the dangers associated with black flecks and iron pipes (if any)?

Cheers

Dave R

[Merryterry]

According to Dr Tom Makin of Liverpool University a bacteria called Gallionella feeds on iron in some water supply situations (not all situations). I shall probably get screamed at by Ostriches who inhabit this group but just passing on information from a world respected source.

[Andrew Gabriel]

None, other than eventually it will leak, but that could be

100 years off yet.

[Ledz]

The clag from the Triton is simply scale- the kettle containing the heating element is quite small and I expect it will be absolutely stuffed with scale- I replaced one a few years ago and out of interest cut the kettle in half- very interesting and quite a shock as it had so much scale in it. I tried getting descaler into it before cutting it open but it it has a clever design to cut down the chance of running dry and it is difficult to get the descaler in in any useful quantity.

[Dave Plowman (News)]

Mains water supplies are chlorinated to kill such bugs - unless you have evidence to suggest the bacteria named is immune to it?

[Rob Morley]

So what?

All you have to do now is show that Gallionella could be dangerous to the OP. You can do that, can't you?

[Alan]

I get a lot of black 'gunk' collecting on the taps and shower head, places in the shower cabinet where water collects, etc. I always assumed it was something from my cold water tank, but since I moved house to a pressurised mains water system I can only imagine it's now coming from the hot water, or the cold main supply. It also collects inside the toilet cisterns around the inlet valve, and under the toilet rim.

I've not idea what it is or if it's harmfull, but it's easily removed.

[Guy King]

The message from Rob Morley contains these words:

It's pretty though - those spiral "stalks" are really neat.

[Guy King]

The message from "Alan" contains these words:

May well be manganese salts.

[<me9]

Black mould. Difficult to remove, and it /always/ comes back. I suspect its spores are harmful to asthmatics/hay fever sufferers.

[Rob Morley]

Indeed - it's a strange little bug to use such an unusual chemistry for its metabolism.

[Derek ^]

I think that's what mine was.

It seemed to be growing on the plastic "aeration" inserts many taps have nowadays. Once it starts it's hard stop it. Probably impossible if you have black mould growing elsewhere in the bathroom.

DG