aargh drains !

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Ollie78

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As you can tell by the title I am having an issue with the drains. We have had a flood emenating from a manhole cover on our drive and one inspection cover in the garage, it`s gone through the airbrick in the garage and under our hung floor too.
There is black sludge everywhere, Thames water say its rainwater and therefore our fault etc. despite the fact that we have combined drainage here (1930s houses) .
Insurance say they will clean it up but that is it, the insurance guy said something to my wife about you "will have to dig up the driveway...expensive..etc" but offered no further explanation, I await his report.

This has happened a few times but nowhere near this badly, I measured the tidemark left on my toolbox and it was 105mm inside the garage so more outside.
We are the last (lowest house) on a long run of 300mm sewer which then t`s into a big sewer at the end of our street about 40 metres away, so when the system gets deluged it can come out of my system first.

Anyway I need to find a solution to this once and for all because it is incredibly annoying. The problem is, I do not know who can provide a plan of action. I can find plenty of "drain experts" who will unblock it but its not blocked or large civil engeneering firms who will not be interested or very expensive.
I need some kind of drainage design engineer or something.
We will get all the drains fully surveyed anyway but even after that I still need to know what to do.

Is there a term for what I am looking for ?

Ollie
 
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First question is, does everything flow into one sewer or do you have one for grey and another for rain water ? A 12 inch pipe is large for just rainwater, how many houses on this pipe ?

We are the last (lowest house) on a long run of 300mm sewer which then t`s into a big sewer at the end of our street about 40 metres away
That's a problem as shiete always flows downhill whether it's drains or management. If it is coming out of your inspection chamber then it is picking the path of least resistance, so why is it not flowing into the big sewer ? obstruction like roots, the big sewer at max capacity which could be as a result of new housing having been built in the area. Black sludge hardly sounds like rain water ! Does it smell of shiete ?

The drain survey is your first point of call to give you a starting point, then once you have that things will be clearer.
 
First question is, does everything flow into one sewer or do you have one for grey and another for rain water ? A 12 inch pipe is large for just rainwater, how many houses on this pipe ?


That's a problem as shiete always flows downhill whether it's drains or management. If it is coming out of your inspection chamber then it is picking the path of least resistance, so why is it not flowing into the big sewer ? obstruction like roots, the big sewer at max capacity which could be as a result of new housing having been built in the area. Black sludge hardly sounds like rain water ! Does it smell of shiete ?

The drain survey is your first point of call to give you a starting point, then once you have that things will be clearer.
Yes, it is one pipe for sewage and rainwater, there is an unconnected higher level pipe that is for the street drains as far as I can tell.
The drain from our house is a single straight run into the 300mm main and is intact because they put a camera down it last time. I guess 50 houses in my street but who knows how long the run is.

I was told by a guy who came out last year when it happenned to a lesser degree that it was basically the system being undersized and could not cope with the storm water ie, it fills up then comes out of the first available place. He said he would report it but Thames water would do nothing.

I know it is not just rainwater it smells quite bad and somehow like diesel as well, the guy who came from thames water on Wednesday did a little swab test and determined it was not sewage.
However, I think that because the storm surge has cleaned the drain nicely before it became overwhelmed then he was confident this test would not show sewage and could fob us off. It is certainly not just rainwater.
I was not in when he came but according to my wife he first said our drain was blocked, my wife told him the drain in question is about a metre long and fed directly into the same pipe and this had happenned before he returned to the van for a fag and a long phone call, then came back with a card saying it was surface water and if we disagree to call thames water !!

Ollie
 
Surely if your drainage run into the main 300mm is clear, then the problem is in the main drain, so is responsibility of the water company.

We had a similar issue a few years back. Turned out main drain was damaged about 400m up the road, so burden of repair fell to united utilities.
Several of the residents had their drains checked up to the main connection, so could prove that we had no issue under our land so united utilities had to chase back the source, which was a cracked drain wall allowing soil in causing blockage.

Not immediately apparent as the soil would sometimes be flushed clear.
 
I don't know if such things are suitable for your situation but you can buy non return valves for sewage pipes. I wonder if one would be able to stop flow in the wrong direction when the system is getting overwhelmed by the main sewer.
 
Surely if your drainage run into the main 300mm is clear, then the problem is in the main drain, so is responsibility of the water company

This is what I think as well. Unfortunately we are using logic and reasoning which is apparently in short supply at Thames water.

@Alli I have looked into this a bit and they are available in varying types, the issue is that when they close there is a very short amount of pipe left in the house side which can still flood with the rainwater, but at least it would only be rainwater then.

Considering something like this thing maybe Clearwater Compact Sewage Pumping Station | Drainage Superstore®

Ollie
 
That looks really interesting, I guess you would benefit for it emptying the sump under pressure so even if the sewer was backing up, it should stop it coming back to you and be able to empty the sump at the same time. Would this be on your bit of pipe to your house or are you thinking of having all the other properties run through it, my only thought would you would be paying to run the pump for all liquid passing through it.
 
That looks really interesting, I guess you would benefit for it emptying the sump under pressure so even if the sewer was backing up, it should stop it coming back to you and be able to empty the sump at the same time. Would this be on your bit of pipe to your house or are you thinking of having all the other properties run through it, my only thought would you would be paying to run the pump for all liquid passing through it.
It would be on my side of the pipe under the driveway, there are a couple of things I like about it. We have a shallow drain with not much fall on it and our drive slopes upwards to the road, with this sort of device we could raise the outlet pipe giving more angle to the pipe entering the sewer. It also says it has an anti backflow valve in it, as well as providing an increased capacity.
I am thinking it should auto pump once a certain capacity is reached so as a storm happens it would just start going and keep going until its below a safe level.
Could put one of these the other side in case as well Anti-Flood Valve with Backflow Prevention | T-T Pumps

I am just getting ideas for now I will try and get proffessional advice before I dig holes !

Ollie
 
The black sludge, maybe slit and a clue.
We live in an old house with drains running everywhere, have come across black silt before the Sewage meets the line.
Digging is not the end of the world as most builders will have you believe.
If your driveway is paving just lift and dig, concrete or tarmac just needs a consaw to cut track.
Utube video are a great education.
Find out if sewage or silt, which I find from kitchen sinks.
 
Contact the "Environmental Agency" if you are not getting anywhere with the Water Company, it does sound as though it's their problem and a hazard to your health.
 
As well as the Environmental Agency you could contact your Local Authority Environmental Health Department for assistance.
To give you a greater insight to this upset have a look on line for:-
1. "Section 24 pre. 1936 Public Sewers"
2."The Private Sewers Transfer Regulations June 2011"
 
As well as the Environmental Agency you could contact your Local Authority Environmental Health Department for assistance.
To give you a greater insight to this upset have a look on line for:-
1. "Section 24 pre. 1936 Public Sewers"
2."The Private Sewers Transfer Regulations June 2011"
Thanks for this, it should prove useful (though our house was built, or at least sold in 1937..) .
@MikeJhn I have considered this option and will look into it.

Ideally what I need is an independent assessment of our drainage system and the main sewer, but not sure who provides this service.
At present there are conflicting opinions from everywhere. If it is thames waters fault it likely does not help us deal with the problem as they won't put their hand in their pocket anyway.
If it is our drain issue then I don't want to make a mistake and need to re do any work I put in.
Currently in the workshop doing some nice dry woodwork..

Thanks for all replies.

Ollie
 
The black sludge, maybe slit and a clue.
We live in an old house with drains running everywhere, have come across black silt before the Sewage meets the line.
Digging is not the end of the world as most builders will have you believe.
If your driveway is paving just lift and dig, concrete or tarmac just needs a consaw to cut track.
Utube video are a great education.
Find out if sewage or silt, which I find from kitchen sinks.
I am not worried about digging etc and I am preparing for what is going to end up being a full driveway replacement and drainage revamp. But i just want a foolproof plan before I start it.
Interestingly as the sludge is drying it is revealing a large amount of what appears to be loo roll !
 
I lived in a 10 year old house with a similar problem....
the row of 8 houses all shared the same drain which ran under my driveway like everybody else.......
in the end the whole pipe top to bottom had to be relaid /replaced.....
all 8 houses paid an equ share of the whole cost....
 
We have a shallow drain with not much fall on it and our drive slopes upwards to the road,
The drive may slope upwards towards the road but the drain needs "fall" and without it then you become a point of least resistance and somewhere for the shiete to eascape.

The drain survey will measure the lay of the land and depth of the drains against a common datum, to much fall is as bad as to little. With this basic info you might find something obvious but always from point A to B there has to be a fall, if the fall becomes excessive then keep the fall correct and you use drop chambers between runs.
 
The drive may slope upwards towards the road but the drain needs "fall" and without it then you become a point of least resistance and somewhere for the shiete to eascape.

The drain survey will measure the lay of the land and depth of the drains against a common datum, to much fall is as bad as to little. With this basic info you might find something obvious but always from point A to B there has to be a fall, if the fall becomes excessive then keep the fall correct and you use drop chambers between runs.
This is part of the problem, our drain is very flat, the fall is minimal but enough under normal conditions.
So, as the drive does go up towards the road I was thinking that putting in a pump station thing I can effectively raise the height of outlet pipe and increase the fall into the sewer. From manhole cover in front of garage to the road is maybe 6 to 8 meters with a rise of maybe 1 metre.
Because of the slope it would give a bit more room towards the high end of the drive to fit the tank and anti flood valve underneath. I see that this type of unit is used in basements quite commonly.
I can`t think of any other way to raise the level at our end.

Ollie are the chambers in your garage and front drive choked with sewage at the moment?
No, they are never full up for long or actually blocked really.
What happens is the storm surge backs up the pipe for a short time and then it will drain once the sewer empties again, leaving behind the scum layer.
This I think, is why when anyone comes to check it there is "nothing wrong with it" and its not "blocked". But a blockage is the only problem anyone is prepared to fix.

Ollie
 
Do you have your house deeds? Ours had a useful site map in the pack, with the layout of the drains in our small enclave of 6 houses, there are spot heights marked. Also have a look online at your LAs planning portal, if you can go back to the original planning application there may be documents including a drainage map.

Could you take a phone video of it all working normally, water running through the chamber and away, then of it backing up in heavy rain. It strikes me that is evidence that 'your bit' is fine and that it's a Thames Water problem. Quite how you get TW to deal with it I don't know, but I wonder of they have a complaints procedure which, when exhausted, lets you go to OFWAT much like the OFCOM/Phone company process. The local env health suggestion is a good idea but they are under resourced these days. And/or write to your MP or local Councillor - they are keen to show that they care. We are always getting 'newsletters' with pictures of candidiates pointing into potholes, drain holes, all sorts of holes. Generally, persistance makes it more of a nuisance for them to ignore you than it is to just get on and fix it.
 
Contact the "Environmental Agency" if you are not getting anywhere with the Water Company, it does sound as though it's their problem and a hazard to your health.
TBH I doubt you'll get very far with the EA as they are drastically underfunded (thank Ms Truss).
 
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