A burst is logged with a grid reference to the metre, because that is how a water company decides what to renew. Eleven bursts in nine years sit inside one sixty metre stretch that is now modern plastic pipe on a modern bed.
I am a network technician for a water company. Leakage and bursts, which in January is all there is.
The recording matters, so I will explain it.
Every burst gets a job, and the job gets a location: a grid reference taken on site with a handheld, to about a metre. Not the street, the point.
Those points build the renewal programme. A company does not renew a main because somebody complained, it renews the ones the map says are failing, and the map is nine years of dots.
I have put a lot of those dots on it myself.
Sixty metres of a residential street have eleven dots.
Nine years. Always in a freeze, always the same sixty metres, and the dots sit in a line along the pipe with no more than about eight metres between the extremes across the whole eleven.
The street either side has two bursts in the same period, which is normal for its age.
What has been done, which is everything.
2018: the section was repaired twice in one winter, which triggers an automatic review, and the review put it on the renewal list.
2019: the whole sixty metres was renewed. Out with the cast iron, in with blue MDPE, which is plastic, on a proper bed of pea gravel, backfilled and compacted to spec, and pressure tested before it went into service.
Plastic does not burst like iron. It is flexible, it moves with the ground, and it is why the industry has spent thirty years replacing one with the other.
It burst in the January of 2021.
I was on that job. A plastic main does not fail the way that one had.
Iron cracks. It goes circumferentially, a clean break round the pipe, or it splits along a line of corrosion.
Plastic tears or it splits at a joint. What is not supposed to happen, and what I had not seen before or since, is a hole.
It was an oval hole in the wall of the pipe about the size of a hand, with the edges turned outward, in the middle of a length with no joint anywhere near it.
Outward, which means from the inside. Which is what pressure does, and it is at pressure, so that part is not strange on its own.
What is strange is that plastic that fails from internal pressure balloons first. It swells, it thins, and then it goes. This had not swelled. The wall thickness at the edge of the hole was the wall thickness everywhere else, which I measured with a gauge because I did not believe it.
2022: renewed again. Different contractor, different batch of pipe, deeper, on the advice of a design engineer who had read the file.
Deeper matters, because frost gets down about half a metre in this country and our standard cover is nine hundred. He took it to a metre two.
2023: burst. 2024: burst. Last January: burst.
Five since it was first renewed and six before, and all eleven inside sixty metres.
The ground.
Investigated in 2022 because a soil that moves will break anything.
Two boreholes and a report. The ground is a firm sandy clay with no significant shrink swell potential and no made ground, and the report says the conditions are not consistent with the pattern of failures observed.
I have read that sentence to three different people.
The report also notes, in a paragraph nobody has ever asked me about, that the boreholes both encountered a band of loose material between about one point three and one point six metres, of unknown origin, which the engineer suggests may be a backfilled service trench and recommends further investigation.
There is no service in that band. I have the utility drawings for the whole street and the only things under it are our main at a metre two, a gas main on the other side of the road, and a telecoms duct that is nowhere near.
The timing.
All eleven are in a freeze, which is what a burst does, so that on its own is the least remarkable thing here.
But I have the temperatures, because a burst job records them.
The air temperature at the eleven is between minus one and minus seven, which is an ordinary British cold snap.
There are, in those nine years, fourteen colder nights than the coldest of the eleven. Nothing happened on any of them.
What I do about it.
I go out, I dig, I repair it, and I write the job up. That is my job and I am good at it and there is no version of this where I stop doing it.
The section is on the renewal list again, for the third time, and it will be renewed again, and I have said in writing that renewing it will not work, and my supervisor agrees with me and has said so upward, and the programme is the programme.
There is one thing I do that is not in the method.
When we open it up I take the offcut. The old length that comes out goes for recycling and nobody counts them, and I have kept a piece from every one of the five since it went plastic.
They are in my garage on a shelf, and they are all the same. A hole about the size of a hand, edges turned outward, wall thickness unchanged, no joint within four metres.
And on the last two, which I only noticed because I had the others to compare with, the inside of the pipe around the hole is polished. Smooth and slightly bright, in a band about as wide as my two hands, the way a pipe goes where something has been running against it for a long time.
That pipe had been in the ground eleven months.