Anyone know what this is? (Garden manhole / drain)

[Madwife123]

Doing some work in the garden. Found the manhole cover was loose while doing so. It’s a huge wide pipe underneath, no water, can’t work out what it’s for and if we even need to keep it. New build so whatever it is it’s relatively new but it’s not on the plans.

Perhaps it is an unexploded device from WW2.

Is there a stop tap down there?

@euclid House built 18 months ago so that would be impressive! 🤣

@ArchbishopOfBanterbury It’s literally a wide pipe that goes deep and then bends away out my garden. Nothing visible in it, no water, no reason it seems to need to be there. I’m wondering if we can cover it. Had planned to go round until realising the top wasn’t fastened on and it appears not in use.

It's to do with the waste plumbing.

A couple of options

1. Rodding point in case of blockage- but will be a gentle bend to enable a rod to go down.
2. Water meter point, but you would be able to see the meter
3. Put in with drains at start of development but plans changed and ended up not using it, not worth digging up so just capped it

Thought of another
-ducting for cable TV to go through but never used?

Does the pipe go toward your house? Diagram please of the location.
Or how about you contact the builder and ask them? Although they will probably be on lockdown.

It’s in the far corner of the garden and it bends away from my garden towards the house behind mine. But it’s very deep.

Soak away from the gutters?

It'll be a rodding point/inspection hatch, for either foul or surface water drainage - please don't cover it!
It's there to allow for the removal of blockages from the main pipe which is probably a little further around the bend.

@Lovetoridemybicycle That’s what I’m suspecting. We had a ridiculous number of manholes when we bought the house, complained and the removed a few that were unused but put in before the drainage plans were complete. So now I’m thinking this might be unused so it’s better to cover it now while doing work anyway. But if it does need access for any reason then I’m gonna be laying a patio over it.

DH was (pre retirement) a Building Inspector.

His suggestion is it might be a borehole.
What approx is the diameter of the pipe?
Geographically, where are you? (roughly) as ground conditions differ.
It might be on the original Planning Permission:
Coal board, Environment Agency consultations?

A soakaway?

@lunarcitysevern There is definitely no water down there though. And if it was a rodding point for foul waste surely the lid should have actually been attached?

I think you can get 'naice' covers for them or a patio tile 'base' which can be removed if you need access and make it prettier.

Madwife despite the fact that the house is a new build, the land will have been there during the war.

@pussycatinboots About 10 inches wide. Here a photo inside also. I’ve dropped a stone in and heard it hit the bottom. No splash.

It's not a standard manhole cover.
It's a borehole to do with a site inspection report which would have been carried out before the development was begun.
Normally they're backfilled, but sometimes they are left so that they can check re: ground water levels.

We are Cheshire and it’s definitely not on the plans. None of the drainage points were as it was changed later.

Or left because they couldn’t be bothered removing it. We’ve found house bricks buried here as well and our fence is propped up on loose rubble.

If it's a vertical pipe for a good distance down, it won't be a rodding point. I would think fairly safe to cover it. You could look at original planning permission documents on councils planning portal to see if another property was proposed there

cross posted
DH said it's definitely the outer casing of a borehole, and the lack of splash is good
Best thing to do is keep the pics, measure where it is and keep a note of that so that if you sell, you have the info if (big if) it comes up on the survey highly unlikely then cover it up with your patio.

The borehole is used to determine the ground conditions which will decide whether your house has strip foundations (1m) deep strip (1m+), Raft founds or piled.

Erm, we're Cheshire too 👋🏻 DH used to work for Crewe and Nantwich and Vale Royal.

Put a glow stick tied to strong down it 🤣 Not as deep as it looks and doesn’t actually lead anywhere