Greenish debris coming from hot tap

[None]

We've had issues for ages now with our water supply. The mains supply itself contains sediment, but the hot supply is giving us problems we are baffled by.

The worst problem is when more than one hot tap is opened and demand is higher around the house. What happens is that fairly large particles, which I can only describe as being similar in appearance to snots (no joke!) flow out with the water. I've been wondering for a good while as to what the hell this stuff can be. You don't really see it with just one tap opened, or demand being lower, but its an unpleasant thing to have in your supply right?

I've talked to plumbers, they don't want to know really (because I presume they have no clue how such crap could form in the hot water cylinder). Live in Dublin btw, and never seen this in any house but mine. Would appreciate input, cheers.

[Chris J Dixon]

Do you have a header tank? If so, have a look in it.

Chris

[None]

There is some sediment on the bottom of the tank, I clean and disinfect it every year. This problem with the hot tap has always been there though..

[JimK]

Is it a private supply? we had something similar a few years ago, lots of sediment in the header tank - since removed for new system - I suspect the snots were hot water dwelling "fungi" or equivalent lurking in the hot water cylinder.

JimK

[None]

We're on a mains water supply, not a private system. It does seem to be some sort of bacterial growth in the hot cylinder, if it were isolated to a pipe length, it would be flushed out eventually. It comes from any hot tap when demand is high in the house,

I just wish I could find out how to get it sorted. We've had our current hot water cylinder for almost four years, and I know it occurred in the previous one too (that cylinder ended up leaking, I wonder if this stuff is corrosive too).

[NT]

bacterial & fungal are easy to sort, put a bottle of bleach in the header tank, leave it there for a bit, then draw enough water for it to enter the cylinder. Flush out through all the taps later. At least you'd eliminate one major possibility that way.

NT

[dom]

I agree its probably bacterial growth, with a firm hold on part of the system walls - hence it dislodges under high flow.

Safer than bleach though, is water purification tablets (the type for using in drinking water in dodgy parts of the world - buy them in Boots) - chuck a whole packet of them in the header tank.

[Harry Bloomfield]

Could this 'growth' possibly be due to your cylinder temperature being set too low? Check the temperature of the hot water as it comes out of the hot tap - good excuse to buy one of those IR meters BTW.

The 'snot', sounds very much like the stuff which forms in car windscreen washers and blocks them. I would be inclined to (besides checking the temperature), turn the supply off to the header tank and drain the entire HW system down, flushing through each tap in turn until completely empty, let it refill and repeat. Finally, set the cylinder stat up to maximum, to kill everything in there and flush again. Finally set the stat back to normal.

[None]

performing another cleansing of the system, using some Milton sterilising solution. Possibly won't be enough to kill very much in the cylinder though... I don't fancy using bleach, could cause issues if someone accidentally uses water too soon afterward.

The cylinder I have doesn't seem to have a stat unfortunately... though the water can get hot enough to really burn your hands, so I would think that wouldn't be too much of an issue.

[None]

[JimK]

Is it a private supply? we had something similar a few years ago, lots of sediment in the header tank - since removed for new system - I suspect the snots were hot water dwelling "fungi" or equivalent lurking in the hot water cylinder.

JimK

[Steve Firth]

And water purification tablets are an expensive way of buying bleach.

[JimK]

sorry for double post :~)(

with the bleach thing you could probly calculate the likely time/"number of cylinders worth of water" to dilute however much bleach you put in down to "nothing".

Size of cylinder + level of water in header tank + rough guesstimate of length of pipework involved = total amount to treat then factor down (using bleach instructions/ideas from on here) how much bleach to put in header tank to treat, how much to draw off to get it into cylinder, how long to leave, how long to dilute down and drain out??

Cheers JimK

[Harry Bloomfield]

None presented the following explanation :

Turn the water off, where it goes into the header tank or tie the float up - then turn all the taps until the all go dry. But make sure there is no source of heat into the cylinder first.

[JimK]

quite a bit of water left in the cylinder after this procedure?

JimK

[Harry Bloomfield]

There will be, but getting most of it out plus the rush of the flow will help clear it.

[None]

[<me9]

Like "completely full". There should be a drain off at teh base of the cylinder (mine's "conveniently" at the back) to drain off te cylinder. Alternatively take off the top connection to the cylinder (after draining off the pipes via the hot tap) and use a hose to syphon out the contents.

[Andy Champ]

Bleach is usually sodium hypochlorite, Na Cl O.

The purifying tables I have are Sodium dichloroisocyanurate, C3 Cl2 N3 Na O3. These are for camping, but the same stuff seems to be used in swimming pools (which might be cheaper for large quanitities!)

Although both smell of chlorine they are different chemicals.

Andy

[Andy Dingley]

What do you think is in Milton?