Finding a water leak - looks like a really tricky one!

My experience with water companies has been very positive. I had multiple leaks in the service pipe due to sharp rock fragments cutting into it. The inspector came and the company fixed the leaks several times, even though they were strictly our responsibility. The cost of the losses was rebated. One leak happened when there was nobody at the property and 19000 m^3 were lost in three weeks with no water visible at the surface. The flow was so great that the water meter under the pavement could be heard rattling from 10m away. This time the inspector suggested that perhaps we should do something to improve the situation , so we had the service pipe replaced and made sure it was completely enclosed in flexible trunking for extra protection. It cost about £1k because the excavator had to work very hard in all the rock and it took a day to dig the new trench. John

Think you might break your neck diving into the ground towards the water sodden area underground...... :-D

Our last house had a communal feed from a stop tap under the pavement, to three houses in a terrace - and maybe to the next 3-house terrace as well.

When we asked about getting a water meter, the answer was "you can't have one" rather than "we will need to run a separate feed from the pipe in the road" - in other words "it's too difficult".

Silly question: why does a single pipe that branches to several houses not allow separate meters as long as they are after the branching point and are therefore only measuring the water that is used by one house?

I've come across many meters that are in the house but readable outside via a transducer.

At our last house we shared a supply with next door and when we asked about a water meter they likewise said they could not do it. Instead they put us on a rate that they expected that a house of our size and number of occupants would end up paying with a meter which worked out less than the rate based on the rateable value .

Clever idea, but I would want to add a meter to it, for a better indication of noise level.

The mic on a phone seems ideal, they are tiny, better suited to high frequencies. There are plenty of apps, able to show the waveform on screen.

A diaphram, with a weight (as per the German vid), with a pipe to transmit the noise up to the phone.

Well it's a few months on and here's an update...

In the end we found that there was little chance of pinpointing the leak ourselves, and next door (where the supply comes in from the street) eventually decided to get a plumber in, who did a lot of listening and used a 'damp meter' (technology unknown). He eventually concluded that there was more than one leak in the system, probably at least under our solid floor kitchen and under the house on the other side. He couldn't get into the fourth house but suspected that there might be a further leak there too.

So in the end the obvious solution is to replace the supply to all 4 houses. The initial quote from the company that detected the leaks was about £1300 per house, but I thought there must be a cheaper way that involved minimal digging and running the shared supply through the voids under the main part of our houses (rather than the kitchen extensions, two of which have concrete floors). I found a local Thames Water recommended plumber who thinks he can do the job for around £400 per house - in our house there will be a small amount of surface pipework in the kitchen, and two of the houses still have voids under their kitchen extensions so will be simple to do. At that price all the neighbours are happy, so when we can finally arrange for us all not to be away we hope to get it all fixed - hopefully in 2-3 weeks.

Any opinion ventured to the cause of the leaks? Say, water hammer/vibration of the pipe against flint or stones or at brick edges of sleeper walls etc

When was the pipe installed?

There was a lot of dodgy copper pipe around in the 1970s and early 1980s.

A few years back I had a leak in pipe installed around that time. I could hear a faint hiss from a pipe under the floorboards. On lifting the floor boards I found a length of pipe with a pin-hole leak. The area around the leak had gone rusty - a contamination by another metal in a copper pipe. I replaced the complete length under the floorboard.

I was lucky that the leak was on the ground floor and in the void between the concrete slab and my floorboards. The area was very wet indicating a leak for a some time but the leak was exiting downwards towards the concrete and not upwards to the carpeted floorboards.

We have now had the entire supply for all four houses replaced in plastic and the arrangement with all the neighbours was amicable and all bills have been settled. It came to just over £400 per house. The new supply runs at the back of the void under the main part of the houses and is in ducting and easily accessible by lifting floorboards. In our house there is about a metre of visible surface pipework in the kitchen before it goes under the sink unit, and I expect I'll box that in.

I had a chat with the plumber about the most likely cause of the leak (or quite likely leaks). He thought there might be leaks under three of the four houses, judging by where he found damp patches under the floors, and suggested that the most likely cause of the leaks would be rust in the old pipes, which would have been cast iron or galvanised steel. Apparently they tend to fail around the joints first.

So > >> Well it's a few months on and here's an update...

We have now had the entire supply for all four houses replaced in plastic and the arrangement with all the neighbours was amicable and all bills have been settled. It came to just over £400 per house. The new supply runs at the back of the void under the main part of the houses and is in ducting and easily accessible by lifting floorboards. In our house there is about a metre of visible surface pipework in the kitchen before it goes under the sink unit, and I expect I'll box that in.

I had a chat with the plumber about the most likely cause of the leak (or quite likely leaks). He thought there might be leaks under three of the four houses, judging by where he found damp patches under the floors, and suggested that the most likely cause of the leaks would be rust in the old pipes, which would have been cast iron or galvanised steel. Apparently they tend to fail around the joints first.

So > >> Well it's a few months on and here's an update...

We have now had the entire supply for all four houses replaced in plastic and the arrangement with all the neighbours was amicable and all bills have been settled. It came to just over £400 per house. The new supply runs at the back of the void under the main part of the houses and is in ducting and easily accessible by lifting floorboards. In our house there is about a metre of visible surface pipework in the kitchen before it goes under the sink unit, and I expect I'll box that in.

I had a chat with the plumber about the most likely cause of the leak (or quite likely leaks). He thought there might be leaks under three of the four houses, judging by where he found damp patches under the floors, and suggested that the most likely cause of the leaks would be rust in the old pipes, which would have been cast iron or galvanised steel - these may be the original pipes dating from about 1900. Apparently they tend to fail around the joints first.

So in the end we have a satisfactory result that should last many years for less that our insurance excess.

Mention of cast iron piping, I thought this might be informative. A couple of months back there was a break in the 4 inch cast iron supply pipe in my road. The SW subcontractors dug down 1m cut 2 clean cuts and a joiner rodded splint repair to the existing piping.

This is a low speed low traffic minor road. But I knew the likely reason for the failure. If they'd dug down another

Round here, another breakage reason is heavy lorries at new house building sites..

The irony of the other local sinkhole problem. At The end of that road is a large SW sewage works. Up to about 8 years ago they removed the "solids" by s*it barge down the local tidal river. But due to sea level rise the tug could no longer reliably shoot the bridges. So now loads of large stinking lorries have to use that road , and presumably consequential 5m deep sinkhole.

Isn't lead the most likely pipe material? Certainly has been in the Victorian houses I've been in . . .