mystery flow noise

[Tim+]

In my daughters kitchen there's a constant background noise of water flowing through pipes. (Mains pressure flow sounds, not trickling noises).

Turning the mains tap under the sink off makes it quieter but it never goes away. Turning the CH (combi boiler) off makes no difference.

I thought maybe it was a flow noise travelling up through the incoming main but when I listen to the main incomer where it passes under the hall on the way to the kitchen, it's silent.

There's no obvious flooding in or under her flat that we've detected so far. Her flat is the ground floor of a three story end terrace house that's been split into flats so it's difficult to be certain about any of the plumbing routes or to know what's "live".

I must admit I'm baffled. Any suggestions?

Tim

[Gatuzo]

[newshound]

When I lived in Bristol, the house next door (Victorian end terrace) discovered that their bath was draining into a small lake a couple of feet under the living room floor. (Broken cast-iron drain pipe concealed within the party wall). This was evidently draining into the ground away from the house (side of a hill) so leaving no obvious signs, until they took the floor up. Obviously, you don't have a water meter? Might it be possible to fit one temporarily on your rising main, so that at least you could confirm or deny an otherwise undetected leak.

Assuming the stop tap turns off flow to all your taps, it's a bit odd that it only reduces the noise. Seems unlikely that this is because of sound conduction from a source upstream of your supply.

[charles]

when I had a leak on the pipe coming in from the road, shutting off the main stopcock in the house reduced, but did not stop, the noise. Has she an outside tap?

[Bob Minchin]

Quite likely a cistern overflow plumbed directly into a drain.

[The Natural Philosopher]

however if turning the stopcock off doesn't stop it, it cant be that. Unless the stopcock is faulty, its upstream of the c*ck.. unless of course there is a header tank.

Try draining the whole system by turning on all the taps after turning off the c*ck.

If it is header tank inspired, Id say your guess that its a bad toilet cistern is a good one. I've had one or two of those.

[Tim+]

Stopcock works. Opening taps makes no difference. No header tanks in my daughter's flat. Nothing overflowing into drains from her flat or one of the upstairs ones.

Potentially possible from the other flat but hard to check as their soil stack doesn't empty into an accessible chamber.

Odd though that I can hear any noise from the incoming main further "upstream".

Thinking about it, the incomer is lead (which may deaden flow noises quickly) and it's possible that the upstairs flats tee off this main near the stop tap in my daughter's flat.

Think I have to go visit the upstairs neighbour. ;-)

Tim

[newshound]

Sounds like a good bet

[harry]

Lift a manhole cover and see if there's any water running to waste. You'll have to look carefully to see it if it's clear..

Maybe a ventilation fan running somewhere?

Some industrial noise/big water drawoff.

Is it 24/7 or does it stop?

Does it change if you open all the cold water taps?

Put a screwdriver blade on a pipe and the handle hard against your ear & thus see if the noise is being transmitted along the pipes.

[Chris Hogg]

Is this the same house as has the damp patch?

Damp patch.....sound of flowing water.....er....nah! surely not!

[Tim+]

Done that.

It's water pipe noise. Loudest under the kitchen sink where the stop tap is.

No big nearby industry.

Can't vouch for 24/7 but it's always been present when I've been there and continues through the night.

Hmm, adding more flow noises doesn't strike me as helpful.

Done that. Noise doesn't seem to propagate back up lead pipe significantly.

Tim

[Tim+]

No reason why they wouldn't have their own stop taps. It was split into flats many years ago. Inconceivable that each flat wouldn't have its own stop tap. Quite conceivable though that the original main supply has been lead upstairs to each flat branching off before my daughter's stop tap.

But there must be some commonality otherwise the noise wouldn't be being transmitted so clearly.

Tim

[Tim+]

No pipework in damp corner. Besides, I've had floorboards up in that room today. No floods or recent damp.

Tim

[Tim Lamb]

In message , Chris Hogg writes

Have we done central heating circulating pump yet?

>

[Tim+]

*sigh*

Yes, it been done. Besides, why would closing a mains stopcock alter CH pump flow noise?

Tim

[Tim Lamb]

No reason I can offer. Not been following very closely. If you have covered all the likely cistern overflow situations including those vented to the pan, it must be external. Can you get your neighbours to close their stopcocks and then listen at the water co's. shut off?

>

[Tim+]

I will do, but as my ungrateful daughter has moved three hour's drive away, it'll have to wait now. ;-)

Tim

[Nick]

I had a problem very similar to this for a couple of years. No obvious leakage and no obvious solution. This was only audible in the middle of the night (quietest time as I live near Heathrow). Most will probably know why I might be taking a short stroll at that time. Turned out to be a small air pump supplying an aquarium . Sound resonating through pipework. Pump located close to, but not touching any, pipework. Also pump at least 6m from noise source. Probably no help to you whatsoever, just reminded me. Nick.

[newshound]

Some might consider that an advantage :-)

[Tim Lamb]

In message , Tim+ writes

They are never ungrateful; just a bit slow expressing thanks:-)