Covered Manhole

[Joseba]

We recently bought a new property in London, a typical Victorian house where the rear part used to be 2/3 wide but has been extended to go to the border of the property.

After all was complete we discovered that there is a covered manhole within the extended area. It is in fact under the kitchen cabinets, so in case of emergency would not be accessible without major damage. This causes major worries for us.

This issue was not highlighted in the survey which surprised me as the survey (a Level 3 full home survey) was otherwise most thorough and detailed.

I am not aware of any build-over agreement but build control and certificate had been obtained for the extension which was build in 1995.

As part of the purchase there was an indemnity insurance. Originally that was requested because of a window that hasn't had conservation area approval, but it is formulated in a very general way.

The attached map is from the water survey. The green dots I added where my manhole is, and where I can see the neighbor's. My assumption is that the sewer is running parallel to the terraces and road and every house has a manhole in the small part that originally was not overbuilt.

I would very much like to have the views of the esteemed expertise in this audience about this situation.

1. Could I expect an indemnity insurance to pay for rectification of this issue? The insurance was obtained at a time when no-one was aware of this issue so it was in good faith.

2. In 1995, would it have been permitted to have a built-over manhole at the time? I can only assume that the kitchen wasn't in place at the time of inspection.

3. I suppose rerouting the sewer is out of the question considering that it is probably running under the whole width of the house. Correct?

4. What are my options to fix this? The only one I can think of is to change a number of kitchen cabinets so that the manhole is at least accessible in case of emergencies. But that's very disruptive and takes away good use of the kitchen.

5. Would it be advisable to inform Thames Water and seek their views?

6. I have read that in such a situation Thames Water would have the right to access even if that involved major damage to the house. Is that correct?

I appreciate that some of these might be very detailed but I am glad for any suggestions and hints.

Thank you very much!

 

[noseall]

I am not aware of any build-over agreement but build control and certificate had been obtained for the extension which was build in 1995.

I'm guessing BOA's came into force at the same time sewers were adopted by the water companies, circa 2011.
Building Control should have overseen what could or could not have been permitted back when the extension was built.

Why fix what 'aint broke.

 

[HERTS P&D]

Are there any other accessible manhole? Did you have a drain cctv survey?

Andy

 

[HERTS P&D]

Also, if this manhole only serves your property, then Thames Water won't care. If this manhole is on a shared drain line then it would be possible to clear either up or down the line 99% of the time.

Andy

 

[johnny2007]

Looks like a shared drain and your neighbour's manhole is very close to yours, so any blockage would be cleared from there.
Then of course if your drain from toilet to covered manhole is blocked, then it would be a bit more complicated.
I have seen drain companies remove the toilet and clear the blockage from there in similar situations, so no much problem.
If you want peace of mind, ask your neighbour to look into their manhole.
You should see a drain going towards your manhole.
If this is the case, there's absolutely no reason to worry.

 

[cdbe]

I believe the indemnity is only to cover costs of being prosecuted for breaches, not any rectification work.

Personally I wouldn't tell anyone at this stage; you might cause problems when you sell the house - you can't use the indemnity route if the authorities are aware of the breach.

The big concern is a collapse of the pipes under the extension floor - but presumably this would be covered by your buildings insurance.

Might be worth doing some investigation - is the main sewer beyond the building line and does yours join it at 90°, is there an internal soil stack (first floor bathroom), manholes beyond the extension etc - you might be able to identify or arrange some rodding access to pre-empt any emergencies.

 

[Joseba]

Thank you very much for your help! It's good to know that TW is fine considering the neighbouring manhole.

Blockages in my own house are more of a concern then. Thanks johnny2007 for the reference to removing a toilet. Very interesting.

My biggest concern is blockage from the kitchen caused by accumulated fat. The kitchen is on the lower ground floor and there is no obvious rodding access.

 

[^woody^]

My biggest concern is blockage from the kitchen caused by accumulated fat

Which is not a concern unless you are operating a lard factory. The biggest cause of blockages is putting stuff down the toilet that should not be put down the toilet

Generally inspection chambers are for accessing the drainage system to inspect for or deal with issues elsewhere, and not the cause of blockages themselves.

 

[HERTS P&D]

I was on a job yesterday with the ground floor toilet overflowing when the flats upstairs flushed theirs. Thames water didn't want to know as they classes it as internal. I had to chop out the toilet wall to access the soil stack to allow me to drill a hole and jet from there. The bathroom wasn't pretty! No external manhole.

Andy

 

[freddiemercurystwin]

The bathroom wasn't pretty!.

Andy

No bathroom is pretty after you've left it!

 

[bernardgreen]

When new owners upgraded the shower room and moved the toilet they lost the back of toilet access to the bend at the base of the soil stack. It clogged on solidified plaster that had been flushed down the toilet.

A ladder and two sets of drain rods and rodding from the top of the soil stack was the only way to clear the bend.

 

[HERTS P&D]

No bathroom is pretty after you've left it!

The toilet was overflowing and the bath was half filled with sewage.

Andy

 

[xm77]

This is nothing!
I knew of a house where an extension had been done umpteen decades ago
The "builders" clearly found the manhole in the yard under where the extension was to go... so simply covered the whole lot over in concrete and built the extension on top.
So the sealed over manhole was now well and truly inaccessible and there it lay for the next XX years.
Until tree roots got into the pipes at the clay pipe joints, worked their way into the manhole and blocked the whole blinking lot solid.

Of course what the 'builders' had done was only discovered after the blockage occurred
I recall the owners had to get in the specialist drain type companies using remote CCTV and high pressure water cutting gear to cut away the tree roots from the inaccessible manhole under the extension

 

[HERTS P&D]

I can beat that:

There is a cul-de-sac near me where there was a plot of land that someone bought. His friend was an architect who made plans, they had a pilling company in to pile the foundations, on the last pile the concrete being poured never stopped. They then realised that they drilled into the main drain line and filled it with concrete. Thames water came out and had to put in a temporary pumping station for all of the houses, this was there for a few months while everything was sorted out.

Now the best part, Thames water blamed the pilling company, the pilling company blamed the architect, the architect said that as he was not employed by the plot owner that he was not at fault. Not sure who payed the bill, but the plot holder and architect are no longer friends.

Andy

 

[noseall]

They then realised that they drilled into the main drain line and filled it with concrete.

Oops.

Kinell.