Grit? in cold water supply blocking taps, washer etc

28 Jul 2015
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United Kingdom
Any of you plumbers got any thoughts on this please.

Brother in law has Worchester heat only boiler, linked to an unvented cylinder. (Centerstore)... was all new in 2013.
He was saying the pressure wasn't very good on his taps... it was the cold feed, which I thought doesn't go through the cylinder (presume that's correct?)

A month after cleaning out the filters on the cold feed, this is what he found.
The washer finally said low water supply, and threw up an error, which is why he investigated it.

Screenshot 2022-11-08 at 12.31.06.pngScreenshot 2022-11-08 at 12.36.08.pngScreenshot 2022-11-08 at 12.37.28.png

The cold water pressure is low on all appliances, taps, showers, washers... hot is better, but he thinks is not 100%.

The water people have checked the supply in the street, and have said there is no problem... but how is this grit getting in his cold supply?

I read about some baffle that might be failing, but there are no deposits in the hot side.

He does have a blending valve or two on the pipework, could this be allowing tank deposits to transfer to the cold supply??

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Does he have a water softener or live in a hard water area without one?
Hard water area yes, but no softener.

It's not white like limescale though?!?
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Looks like limescale imo, have an internet search of limescale in water pipes
Stange how it's only just started?
Even found it in the toilet cistern filler. Looked more like grit to me.
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Stange how it's only just started?
Even found it in the toilet cistern filler. Looked more like grit to me.
Limescale formation doesn’t happen overnight
Limescale formation doesn’t happen overnight
Would you be talking about lime in the pipes before the water meter? as the house was only built in 2013.

What would be the solution, other than a strainer fitted?
Take a little of it and see if it dissolves in a limescale remover, if it doesn't it's grit, if it does it's limescale,

If it's grit/sand, it may be a recent mains pipe burst has allowed some of the bedding material to be drawn in.
Limescale remover... could I use lemon juice? have these sat around ;)

Limecale will fizz and quickly disappear completely

Concrete will fizz less and the sand will remain.

Sometimes people installing pipes push them under floors and the open ends scoop up builders rubble.
Thanks all for comments so far.

It looks like it is grit, as last time we had this we used vinegar, as not much happened.

BIL is going round in circles with this, today the cold taps are dribbling (apart from one tap!)
The toilets cisterns are overflowing, grit again in the fillers.

If this 'grit' has got into the house from external burst pipe for example, can this grit make it's way to the unvented tank?
How do you go about cleaning them out? not BIL, the plumber will do it.

If this 'grit' has got into the house from external burst pipe for example, can this grit make it's way to the unvented tank?
The combination valve group should have a strainer/filter on it.

I'd also recommend getting and inline one onto the incoming mains if it's creating a problem until it clears.

How do you go about cleaning them out?

After you take off a tap or valve to clean it out, you turn the water back on, and let it gush out, at maximum pressure and flow, from the open pipe, and this will wash out a lot of the contaminant

I have a fire hydrant outside my house and the water co do something similar after they have been working on the supply pipes down my lane. They gush it out onto the road.
Thanks for this.

The water company have done the fire hydrant thing, and pronounced it clear... a month down the line they are back at the same position.
Not sure the water company will come out again, but they will ask the question.
What operation, if any, has been done to flush the length of pipe between where the hydrant tees off, and the house appliances? It's a long length of pipe into the house; opening the hydrant will have done nothing to clear crud after the split

Fit a whole house water filter?

Install it high up the wall enough that you can get a bucket under it

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