Public Drain Blocked - Sewage Flooded Underfloor

[Foolish_]

Hi guys,

Once again, thanks for the great advice.

I attempted to book a drain survey via Dyno(Rod), but they would accept the booking due to lack of manhole access, and refused to touch the access point that thames water pulled up (although it is poss too far away anyway). They advised me to contact Thames and get them to assist given they caused the issue. Called them, but didn't get anywhere with the first line callcenter. They have escalated to the Waste Team and waiting for them to get back.

You really need to locate all the chambers, and get an accurate idea of what's going where firstly.

Yes - I have managed however to locate the 7m manhole and it is located outside the property in front of the front door, so I have the option of uncoverring that and getting a private survey done. I also spoke to the neighbour about getting access to two inspection points on his property. He granted access and i took a quick look last night and its now apparent that I do have a drain running underneath my house that comes from the neighbouring property, and most likely is connected to the blocked sewer somehow. I think I now have enough info about the external points, and if ?I can uncover the one outside my front door, that should be enough to allow an inspection. Alternatively I could push Thames to do another inspection given there is an unchecked public (due it it serving another property) drain running through the house.

Does seem a bit odd though why the system isn't taking the most direct route to the road, do you know if the drainage predates the property?

Yes - I think part of the house was built after the drains were in place.


@ KenGMac - Thanks for the excellent insurance advise. I'm saving that guide for future use also. I'll give it another go today.

Updated overview including new access point flow info attached.

 

[Ian H]

It's definitely a water board job. Forget DynoRob.

 

[Keithmac]

If all your neighbours waste feeds into the pipe running under your house does that not class it as a public sewer so the sole responsibility of the water board?.

 

[Foolish_]

Hi. Sorry for the delay in getting back to you. I've had to go abroad, which is a bit bad timing given the circumstances, so wasn't able to update.

Quick summary.
- Thames water not being that helpful despite causing damage. Basis being they are not responsible for private assets

- I raised that it seems that the neighbouring property seems to be running under my property. They said they had no record of this, and it would depend on whether the neighbouring drain ran straight to the public line, or joined with my own as to whether it was their asset or not. I asked them to CCTV the neighbours drain to determine whether it was going mine (ie, a Thames asset) or went straight to the public line (ie a private issue between myself and the neighbour). They agreed to do this, subject to permission from the neighbour, and would get back to me in a week or so.

- in the meantime I manage to locate and dig out the 7m manhole in front of my front door and convince a drain surveyor to do a last minute inspection. We found that all my drainage (including the 14m manhole) comes into here and joins the main Street drain (4 houses).

- he surveyed the main drain and spotted root damage that could have been linked to the original blockage.

- He also found that there is an underground chamber of some sorts around the kitchen, and it was probably this that got breached causing the flood.

- Finally, he found that the neighbouring property does join into the above underneath my house. Presumably making it a Thames asset, though hopefully not resulting in them needing to knock my house down to access :/

I'm still awaiting the official survey write up, and the findings of Thames check on next door, but I'm hoping this is enough get Thames to start taking things a bit more seriously.

Thanks for the help guys. I'll update when back.

 

[Foolish_]

Hi Everyone,

I got back in UK two weeks back and thankfully the house wasn't underwater again

Whilst I was away, I know (via a neighbour) that the water co turned up and gave the street sewer a pressure wash to clear out the roots/grime that could have contributed to the original issue. I also received the written results of my own survey confirming the shared / public sewer connecting to my neighbour. No further communication from the water company though.

Since getting back I went hunting for the chamber that was found during my survey. Two failed attempts at crawling through the floorspace (still a bit damp) and two holes in my kitched floor later and I've finally located it. There is a damaged inspection chamber underneath the suspended floor of my kitchen that would appear to be the cause of the flooding. It looks like the top has popped off this inspection chamber under the build up of pressure caused by the block on the main street. As mentioned earlier, in the past the water escaped through another unsealed IC on the street. This time though, the seal has been blown off the IC under my kitchen. The seal is still actually screwed into a collar, but it looks like the seal between the collar and the IC itself has failed. I've attached a couple of images below. I'm not sure if this will work, but here's a video hosted externally of it's innards: https://www.dropbox.com/s/zbhffooa4lyonex/IMG_4197.mov?dl=0



To summarise, it drain layout is as follows. Green being my responsibility, and red being the water co's. As you guys mentioned above, deff a water board job.

Water board wasn't helpful before as they were assuming it was my own private asset that failed (despite me telling them I thought otherwise). Now that I've located and got access to their IC, and confirmed it serves another property, I'll write to them asking them to reseal, sort out the damp problems that are still down there following the flood, and reimburse for the drain survey and damage incurred to kitchen looking for this. If anybody has any thoughts or advice on what else to ask/say when contacting them, that would be really appreciated.

Two quick question if I may:

Whilst looking into this, I keep seeing mention of requiring build over agreements with the water co - and sometime retrospective build over agreements. As far as I know, this part of the house was build in the 70's or 80's. Would that mean I am except from this?

Also, are there any potential issues with building regulations if say they didn't sign off on building over a public sewer back then?

Many thanks!

 

[bernardgreen]

My suggestion would be to close off the pipe under your house and have a new sewer to the street as in purple here

Re-direct your kitchen wastes into IP2 so the new sewer is a shared service is a shared service and thus not your neighbour's responsibility.

For the Water Company creating a new sewer may be simpler and cheaper than making the sewer under your house safe now and then maintaining it in the futures

 

[Hugh Jaleak]

My suggestion would be to close off the pipe under your house and have a new sewer to the street as in purple here

For the Water Company creating a new sewer may be simpler and cheaper than making the sewer under your house safe now and then maintaining it in the futures

Not always that simple, the Water Co are not likely to want to spend that sort of money, when simply sealing the existing chamber under the floor will suffice. Also Legal issues with easements, a hell of a lot of disruption whilst the work is done, and for what? If there was a issue with the main in the street, then jetting that may have removed the issue, (be it FOG/roots/silt/unflushables/whatever), and hopefully the issue will not reoccur any time soon.

I suspect there would have to be repeated cases of internal flooding and compensation paid before any major remedial works will be entertained.

 

[Hot&Cold]

I purchasd proerty about 18m ago

Whilst acquiring the property,Were you made aware of any previous flooding and any rights of agreement re services crossing your property ? These and many other questions are asked in the law society property information form TA6,although the vendor does not have to answer these questions .

The previous owners could have already asked Tw to adopt the shared drain,they could have refused but Tw wont tell you that. Something about data protection .

Hugh Jaleak ^ has mentioned sealing the offending chamber,best advice

 

[75pete]

Little point to remember, always ask for a Customer Contact number. This is your case raised number on Thames reporting system.
Pete

 

[Foolish_]

My suggestion would be to close off the pipe under your house and have a new sewer to the street as in purple here

I'll discuss the above with the water co. The new purple section is approx 15m and would run though the neighbours recently laid paved area. Something I should mention that I haven't before is that the section that runs under my house is a 100mm pipe. The neighbouring property is a part of a care home. It was originally a 3 bed detached building, but recently they added an extension to the rear with another 3 or 4 rooms. I think all of these are now directed into this 100mm pipe. The drain survey guy suggested that was quite a big ask for a small pipe. Getting things redirected would be ideal for me, but yeah, as Hugh mentions, possibly too much to expect. I'll raise it though.

... simply sealing the existing chamber under the floor will suffice....

Am I correct in thinking that the sealing should be done by the water co rather than myself/a private contractor?

Whilst acquiring the property,Were you made aware of any previous flooding and any rights of agreement re services crossing your property ?

I had a look at the paperwork this morning. Previous owner did complete one. They indicated that there had been no flooding in the past. They also indicated that there were no shared/public drains crossing the property (to their knowledge). When the flooding first happened, one of the neighbours told me straight away that it was probably an IC under the kitchen. He knew about it as he had been shown it in the past by somebody who had previously lived there (not sure if owner / tenant though). He also claims to have brought it to the attention of the guy I bought off. I did call the seller to ask about where manhole covers were located and also asked him about the IC, but he denied all knowledge :/

Little point to remember, always ask for a Customer Contact number. This is your case raised number on Thames reporting system.
Pete

Thanks, sound advice.

 

[bernardgreen]

Sealing the lid of an inspection chamber does not seal the brickwork in the walls of the chamber.

A house near here has an inspection "pit" with a "sealed" cover in the cellar. The lid is 3 brick courses above the cellar floor and when the main sewers back up (*) liquid is forced out between the bricks above the floor. It isn't known how much liquid permeates under the cellar floor.

(*) the house is close to the sewage pumping station and only when the pumps fail do the sewers back up.

The neighbouring property is a part of a care home. It was originally a 3 bed detached building, but recently they added an extension to the rear with another 3 or 4 rooms.

A care home increases the number of rooms and does not upgrade its sewer connection. Do the new rooms have en-suite toilets ? I find it hard to believe that the care home was allowed to add more rooms and still rely on a shared sewer that ran under an adjacent building

 

[Hugh Jaleak]

Its not a brick chamber though in this case, it is a clay chamber, probably made in one piece, as due to its diameter it wont be very deep. The correct cover looks to have been fitted, although the method of fitment may not have been adequate, given the hydraulic pressure created by the blockage.

If pumps are failing causing repeated flooding issues, then the problem lies with the pumps rather than the system. Can never totally rule out pump failure, but a good system will have back up to prevent overflow from the pump station in the event of a pump failing.

Care home may have increased to possibly 7 bedrooms, but even with a toilet in each, and 2-3 extras for staff and visitors, it is highly unlikely all would ever be flushed at once, so a 4" drain would be classed as adequate to accept the flow. Surprising how many homes could be put onto a 4" drain.

Once it leaves the property, the drain is technically nothing to do with the care home either, so any designs for the extension would have not been concerned with the condition of the sewer outside the boundary. Unless the neighbours at the time flagged up concerns with Building Control at the time, it is likely to have been passed.

 

[bernardgreen]

but a good system will have back up to prevent overflow from the pump station in the event of a pump failing.

Tankers collecting the sewage and taking it by road a few miles to the sewage treatment works.

 

[Hugh Jaleak]

Yes, its oh so simple isn't it.... Most pump stations of a reasonable size will have a duty pump and a standby pump to take over if there is a problem with the duty pump. Doesn't always happen though, and other circumstances can have an affect.

Any failure has to be spotted/noted. Personnel then need to attend to ascertain the issue. Is it a blocked pump, power failure/split in rising main/corroded guide rails meaning pumps are unseated/something else...? There could be a number of issues causing a high well level.

Tankers then need to be found and deployed. Ever tried getting a vacuum tanker at short notice at 3 am ? Private contractors are not allowed to discharge outside office hours at most sites to prevent unmonitored dumping of unsuitable/toxic wastes that could kill a STW. Site staff sample loads before discharge to ensure suitability.

 

[Hot&Cold]

Foolish_At some time you will need to splash some cash,if you want a fight with Tw for adoption good luck there as previously mentioned they will have records before you purchased the property.

consider having your own drainage corrected so it does not overflow in your floor void and consider asking your neighbour's to contribute to your drain maintenance,again splashing some cash will reduce you splashing about in others shytte .

it needs fixing but asking Tw and your insurance company to sort is the first line of approach. They have failed to reach a resolution (maybe they mugged you off-who knows) so an alternative approach is required .