Hi, I’m hoping for some plumbing advice…

For years, if you turned a tap on while the loo was flushing, the pipes made a creaky rumbling noise. We worked around this by trying not to use taps/shower/washing machine at the same time.

I’ve assumed that “something” in the cistern needs high water pressure, and sharing the cold feed reduces the pressure causing it to get shirty (excuse me getting technical there)

In the last few days the noise has started happening every time we use the loo, even if taps aren’t being used elsewhere.

Are there any obvious things to check to work out what’s causing it?

Anecdotally, I’d say that the water pressure from the bathroom tap doesn’t seem as high as usual; normally if you turn the tap once it has enough pressure to splash up off the bottom of the sink whereas it needs 2 or 3 turns for that to happen now. Although in my desire to find a cause, I might just be imagining this….

There are no obvious leaks anywhere, although I haven’t checked to see if the meter is moving when no water is being used, to indicate if there’s an underground leak. Although I suspect it would have to be a serious leak to reduce the pressure that much!

Any help gratefully received 🙂

Forgot to say the noise doesn’t specifically seem centred around the loo. I can’t quite track it down, but seems noisiest in the (former) airing cupboard where the pipes run up through it to the combi-boiler (in the loft).
There are various pipes running up there and it seems to be the cold-feed that’s vibrating.

Although the original noise pre-dates us switching to the combi.

Check that the main stopcock isn’t either almost shut or fully open. Changing it will alter the rate of flow and might affect the pipe noise.

As a PS to the above, I read a similar post yesterday on DIYnot.com and there was quite an interesting solution recommended: close the mains stopcock and open every tap and valve then completely drain the entire mains-pressure cold water system. Then open the stopcock a little and allow the system to refill slowly, going round closing taps as the water rises inside the system. This might help any trapped air, which can cause vibration, to leave the system. A further suggestion was to introduce a detergent into the rising water as this would help to break the surface tension on any bubbles and encourage foaming, which will flow along a pipe rather than sit as a bubble would. Not sure how you would get the detergent into and out of your cold water system though! I guess you could crack open a pipe somewhere as you drained the system and squirt in a few CCs of dishwash liqud then stop draining when it emerged at the drain point, then refill slowly and flush everything through thoroughly before drinking any of the water. It would need to be a slow refill or your WC cisterns would foam interestingly!

Just to ditto the above suggestions.

For various reasons I’ve been draining my cold system a fair bit recently, and if it’s half full/got air in you get some odd noises.

Generally sorted after emptying by opening all the taps, then opening up the stopcock to refill it then closing them all off once they’re all running (generally flush the loos to get those pipes filled too).

I drain it at the lowest point remembering to open all the upstairs taps etc so the water can flow back out the pipes.

Anyhow, my experiences back up the suggestion to drain and refill slowly.

If you’ve got an outside tap this will generally be at the lowest point in the system, so turn off the stopcock, open the garden tap and go round opening everything and flushing the bogs. Then do the refill.

Cheers for the suggestions, attempting to drain and refill seems sensible, just not sure how the combi would cope with the system being drained…

There is an isolator valve for it, but I guess using that would risk trapping air at the valve when the system is refilled.

Just had a text from MrsV to say it’s not been doing it this afternoon, guess it’s possible that if air was trapped in the system it’s worked its own way out…

If only all DIY jobs were that simple!

Do you have an old fashioned float valve in your toilet? We have had some seriously noisy plumbing caused by one in the header tank in the system. When they get old, they don’t work as well, because the insides have got worn or furred up, so they don’t hold the valve open very well when filling. Thus you get the valve opening and shutting against the flow of water, which vibrates the pipework, which makes a lot of noise. So you could find that the higher pressure is keeping it open, but when you open a tap, the pressure drops, and you get the rumble. And now it’s properly knackered, so moans all the time.

Maybe.

We have a crap toilet* (cheapest one Focus did about 13 years ago) which has had the (crap plasticy) internals replaced at least once.

The valve flapping seems a reasonable suggestion. We’re also in a hard water area so it’s possible a bit of scale has (temporarily wedged the valve…

A bathroom refit is on the horizon, and there’s one or two things lately that are making the Horizon get closer and closer…

* pun intended

Do you have an old fashioned float valve in your toilet? We have had some seriously noisy plumbing caused by one in the header tank in the system. When they get old, they don’t work as well, because the insides have got worn or furred up, so they don’t hold the valve open very well when filling. Thus you get the valve opening and shutting against the flow of water, which vibrates the pipework, which makes a lot of noise. So you could find that the higher pressure is keeping it open, but when you open a tap, the pressure drops, and you get the rumble. And now it’s properly knackered, so moans all the time.

Maybe.

Had the same thing with vibrating pipes when the bog flushed and swapped the ballcock to new style fluidmaster fill valve (my first ever foray into plumbing). Dead simple to do and dealt with the noisy pipes and fills the cistern quicker and more quietly too.

Woo hoo, fixed it.

Turns out it was the filler valve. The more I thought about it, I realised it’s done this before… Weirdly I had a spare valve in the garage so it’s all sorted now.

Thanks for the pointers 🙂