Found hole in garden

[PearlHeart3]

Hi all, posting here in traffic as I posted something over in the garden section that never had a response.

We are in the process of ripping up decking in our garden that was laid by previous owners approximately 8 years ago. We discovered a hole straddling the boundary separating our garden with the neighbour's. At first we thought it might have been an old sewage pipe and the hole an access point, but I've shoved a torch down there and took some photos. There appears to be an armoured cable in there which is coming out/in to my neighbours side.

The hole is approx. half a metre wide but underneath it goes back further in a round shape and is approx. 2 metres wide. The next door neighbour appears to have put concrete over the top on their side and lots of gravel. I've attached some photos of the area to give you an idea of scale. It's really hard to describe!

Does anyone know what it might be? Or who I should contact about getting it checked out? Would a surveyor know? Feel free to ask more questions!

I'm confused because those lead pipes are usually for clean water supply, not waste water drainage.

I’ve only come across vitrified clay soil pipes for foul drains (I’ve dug plenty of them up over the years), and that lead pipe diameter looks far too narrow for foul drainage?

On this photo there looks to be a contrast between the material forming the wall of the cavity (OP describes it as domed) and the infill material in the base, so I’d be tempted to think it’s an artificial structure where part of it has fallen in rather than a washout from a leaking pipe.

Hi all, so a little update for you.

First, my surveyor called today and after having a look at the plan of the house and my photos, his first thoughts are an old well. The reason he said this is because of the shape of the hole, also because this house and next door used to be owned by Father and son in 1906 (it's all referred to in the deeds) so he said they might have shared a well. He will be paying the garden a visit next Tuesday so I'll update again then.

Second, I took some better photos today. It was overcast but the flash on my proper camera showed more detail. You'll be pleased to know the frog is still there.

A couple of things to note: I do have a matching pipe/cable on my side. I turned my camera around to face my house inside the hole and found this was the case (see attached image). You can also see the round (domed) walls. I have also attached a photo of their pipe again and you can see it comes out just behind their side of the hole entrance (which as I've mentioned previously, is covered up with concrete).

The pipe does look like lead. At the front of the house is a ground floor bay window and there used to be a lead pipe which fed the rainwater from the bay window roof into the drain pipe on the wall. I only discovered this when the lead flashings came away and I had water leaking through my living room ceiling as the pipe displaced a couple of years ago. The two pipes look remarkably similar. I'm not sure why this would be feeding waste water either - could it potentially be used to carry the rainwater away from the gutters at the back of the house? I do have guttering from the roof at the back going into the ground round about where the hole is.

Anyway... onto the photos.

A little bit of decking fell down there too, oops.

@SabrinaThwaite Thanks for your comments. By foul drainage, do you mean like toilet waste? If so, I meant kitchen water waste (sink etc). Would the lead pipe be okay for that type of waste? I know soil pipes need to be wider to accommodate wide loads as it were.

A well is a possibility, as Victorian properties built before public water supplies were installed often had a well, located near the kitchen / scullery to make lugging water inside easier. They fell out of favour once public water supplies started being connected to houses, not least as they tended to be a disease risk.

The lead pipe may have been connected to a hand pump - maybe even to a pump in the kitchen / scullery? Edwardian all mod cons.

Foul water is generally the wastewater from toilets, kitchens, utilities and bathrooms etc. In older houses (like yours) with mains drainage everything (foul water and surface water from the roof) generally flows into the foul drains which run to the foul sewer.

I used to be a sewerage engineer and although it was a long time ago I don’t recall ever coming across a lead sewer pipe. Old sewers would tend to be clay.

Water supply pipes can be lead. The pipe in the photo looks far too small to be a sewer. For a private house they’re normally 6”.

I think an old well as well! . Either with an old water supply running through it or could it possibly be a metal brace of some sort to keep the well shaft supported/braced?

That pipe looks like it emerges from a slot in the structure wall. If it is lead then I don't think it wouldn't be much use as a brace.

Another interesting thing (to me!) is to look up your local geology/

mapapps.bgs.ac.uk/geologyofbritain/home.html?mode=boreholes

And if there are any borehole records near you, it can give you an idea of the depths of the different soil types and sometimes a water table depth.

I've figured it out. The answer was lying in my drawer all along. After reading the deeds carefully, I realised it was a rain water cistern. The deed reads as follows:

THE RAIN WATER cistern between the property hereby conveyed and Number [NEIGHBOURS ADDRESS), aforesaid is a party cistern and shall for ever hereafter be maintained as such.

So that's why it's domed shape and has those lead pipes on each side. I guess I should call my surveyor tomorrow and ask him to stand down.

On the plus side to all this, I've been down a rabbit hole online this evening looking at boreholes (thanks @NotMeNoNo ) and checking electoral registers to find out more about the type of people who lived here. It's been quite a fascinating adventure. Thanks to everyone who contributed to this thread.

And the winner of this thread was... @TonytheDog because he correctly identified the hole in my garden

@PigletJohn thanks for that bit of info. Used to keep the kiddies quiet whilst we were renovating, to watch the glass in case it moved 😊