Public Drain Blocked - Sewage Flooded Underfloor

[Foolish_]

Hi DIYnot'ers,

Please could you assist me with a stinky situation that has lead to the underfloor of my house being flooded with sewage?

Around Sept 2017, the street that I share with 4 other properties became flooded with sewage twice in a short period of time. The sewage was escaping from an inspection point (IP1 on diagram) towards the read of my house. The source of the leak was slightly elevated relative to the floor of my house. The water/drains company attendend, and on each occasion they cleared an obstuction about 7m from the inspeciton point.

Now, approx 3m later, there has been a similar incident, but the results were a little more unpleasant. A few days ago we noticed that the drains weren't clearning very well. There hadnt been any issues on the road like last time, so assumed it was a local problem and applied drain cleaner over night. In the morning, noticed that things hadn't improved, but left it for the time being. Later that day, I heard what sounded like a large rush of water, followed by the toilets gurgline and with their water levels sitting low. Within a few minutes there was a terrible smell. I manged to figure out that the smell was coming from underneath the house so opened up the floor with the intention of going down to take a look. Unfortunately, the entire sub floor had become flooded with stinky water to a depth of about 1.5 inches.

Still assuming it was an internal issue, I called a company out to inspect. The first thing they checked was the inspection point that had previously overflowed, and found that it had again become blocked, though this time instead of overflowing into the road, it had managed to find a way into my uderfloor.

They put me on to the water company, and they came out for a third time to unblock the street drain. Again there was a blockage around the 7m point. After unblocking, they hoovered out the internal flooding as best they could and performed a CCTV inspection.

What they found was:

- The drains were now pretty clean
- At the 7 meter mark, there was another manhole and what looked to be my property joining the drain from the left hand side.
- Just past the manhole there is what looked like a sealed join from above.

They weren't able to locate the manhole in the street. It could be that it is burried under the road. Alternatively, it could be that is located under the property. I'm going to get a metal detector and try to resolve is location


I've drawn a diagram of the layout as best I can. It's not clear to me whether the drains actually run in a straight line from IP1 to the main sewer manhole cover in the road (Marked by line A), or whether the drain runs from IP1 along the road next to my house (Marked by line B). Both of these possibilities seem odd though as (A) would run a shared public sewer under my house, and (B) would have it joining the main sewer away from the manhole in the road.

A few final bullet point facts...

Drain shared with 4 other proprties.
If the missing manhole is under the house, that part of the house was build in the 1980's.
There are two inspection points roughly directly opposite the 7m mark on the other side of the house (IP2 and IP3) on a neighbours land. It could be that these are running under my property into the 7m manhold spot, but I'm not sure at the.
My house joins drain after the inspection point

My working assumption is that I have something under my house such as a sealed manhole that is connected to the drains that were backing up. In the past it stayed shut, and the water backed up into the street, but this time it broke, and all the backed up water has escaped into my property. If this is the case, it's quite likely I'll have future issues whenever the public drain blocks.

I'm still trying to get my head around what has gone on. I'm waiting for the underfloor to dry out and probably go down there in a few days to investigate, but I'd really appreciate it if anybody could help on the on the following. x:

Any thoughts / suggestions on how so much water could have got from the sewer into the subfloor. It did not escape from up the toilet/bath/sinks. The onset of the smell was accomanied with quite a bit of rushing water and gurgling, so I'm assuming something just gave up, but I'm not sure what.

If it turns out it was from a manhole underneath my property, who would be responsible? I can understand issues with private drains being my own problem. But if the manhole was servicing either the neighbour with the 2 instpections points, and / or the 4 other houses on my street, would that make it a public drain and the responsibity ot the water company?

When researching, I came across the term, 'build over agreement'. I'm not sure I have / should have one? I purchasd proerty about 18m ago, and as far as I know, the problem area of the propert was buildin the 1980's

Is this something that I can / should be getting either my insurance company or the water company to resolve? I've tried reading up on this, but between possible 'defective work' and 'private asset' clauses, it's pretty confussing.

On the assumption that this is going to happen again, what could I do to prevent it? I've seen there are products such as a non return valve that could be fitted to a manhole, but presumably I'd need to find the manhole first Are there alternaives, and what type of tradesmand would I need for this? Is it a plumber or somebody more specialised?

Appologies if some of these are stupid questions, and many thanks for any advice given.

 

[KenGMac]

Foolish_

Try an insurance claim?

Contact your House insurer and let them take care of the problems???

Ken

 

[Ian H]

You need a drainage company. Your buildings insurance would likely send an engineer who should be able to find the manhole at the 7mtr point.

They would use drain dye to test for shares and establish a cause of damage. If it's a private issue the insurance company would fix it, if not they would pass it back to the water board.

 

[endecotp]

You don't want a metal detector; there is a particular type of detector - a "cable avoidance tool", "CAT" - that is used in combination with a signal generator. The signal generator goes down the drain, with or without the camera, to the point of interest, and then you wander around on the surface with the detector. It's not as precise as you might hope but an experienced operator can probably work out where to dig.

 

[Ian H]

You can get the exact point if you use them properly:

 

[Nige F]

You can get the exact point if you use them properly:

Blimey, working like that I bet you can peel an orange in your pocket It's close between you and Nose posting pics. of good work.

 

[Ian H]

Thanks Nige, that's a nice compliment

 

[Nige F]

Credit where it's due - it's just that me and my builder M8's are all to old to have taken photos of work, and most of mine was hidden anyway. Pics. keep us oldies interested and shows the DIY'ers what can be done.

 

[Doggit]

An insurance claim will deal with the damage, but I'm not sure if they'll deal with the cause. If there is a drain under your floorboards, then that needs changing for a sealed type. Now is there something at the 7m point that's snagging things and causing the blockage. Is there young kids in the other properties that they might be throwing nappies and wet wipes down the loo.

If a joint has come loose under the floor, then you'll carry on getting seepage into the floor, so they'll need to put a camera down your pipes to check for that next.

 

[bernardgreen]

But if the manhole was servicing either the neighbour with the 2 instpections points, and / or the 4 other houses on my street, would that make it a public drain and the responsibity ot the water company?

If a sewer serves other properties then yes it is the responsibility of the water company to maintain that sewer, My understanding is that if such a sewer becomes blocked and as a result a private sewer backs up and over flows (*) then the water company are responsible for the cost of clearing up that over flow from the private sewer.

(*) that includes excessive leakage that would not have happen had the private sewer been able to discharge freely into the sewer maintained by the water company

 

[KenGMac]

but I'm not sure if they'll deal with the cause.

Generally, all insurance Companies will cover [pay for] such repairs, why? because in Insurance principles what the Insured cannot see the Insured cannot ensure that these component are maintained and in good condition??

Plus all Insurance Policies have a Clause that covers accidental damage to "Underground Services"

Bottom line is contact the Insurer, let them send in a drainage technician, that will generate a report that points the finger as to who pays at either the insurer or the local Water Board, plus the drainage companies survey by CCTV will locate the drain runs and any buried Manholes Etc.

I work Freelance for various Insurers, and Loss Adjusters. In this capacity I have on numerous occasions ripped up flooring to de-contaminate the underfloor areas in several properties not a pleasant job, but quite costly, generally a Kitchen when the Property owner has to move out [the costs rise??]

As my original post contact your Insurer?

Or to save on your future premium hike with your present Insurer do you have any other insurances for say domestic appliances + services? such cover is offered by all major utility providers, do you have such cover?? if so use them your Property insurance Premiums will not be affected???

If you do opt to use your Property Insurer, then when the renewal comes [with a cost HIKE!!!] in try "Go Compare" that is why it is there???

Ken.

 

[Foolish_]

Thanks for the excellent advice and feedback guys.

I have spoke with the insurance, though they haven't been as accommodating as I'd like. They have advised that as it appears to be caused by a blockage in a public sewer that I should take it up with the water company in the first instance. The confirmed that they would cover trace and access, plus any damage to property due to the water, but not the repairs to fix the cause (if say it was a broken pipe). So I'm basically stuck between the water co and the insurance both trying to back away from it. It's a shame, as some of you seem to have dealt with more proactive insurers than mine based on the comments - maybe I'll be going to GoCompare regardless at this rate

In other developments, I spoke to the previous owner of the house and he managed to help me locate a burried manhole. It wasn't at the distance that the CCTV found however, so there is a good chance it is a different one. This manhole was about 14m away from where they did the inspection (ie, an extra 7 m). Additionally, the connection was angled in the opposite direction to what I was expecting (ie, away from the main sewer), and the water was flowing back towards where the mystery buried manhole at the 7m point. Only the bathroom seemed to be feeding into it - the kitched appears to be going elsewhere...


I've updated the diagram to show this. I'm wondering if the two bits I know about meet and then run under my house, perhaps to the other inspection points (IP2 + IP3) that are on the neighbouring property. If it does run under my property, on one hand it is good as, despite being on private property, given it is serving multiple properties, I believe it is the water company's responsibility to look after it. On the flip side, it might be bad due to them possibly having the right to knock my house down to access them

I guess next steps are to have another discussion with the water company on the basis that issues with their drain has caused damage to my property, and it might be that there are shared drains under my house. I'll also approach a company about a drain survey and get this all mapped out.

On other points - I don't have the domestic/utility cover (though i will in future), and no babys/nappies on streets.

Once again, thanks for the help!

 

[Ian H]

If it is like your drawing the 7mtr manhole would be a possible cause due to its design. Depending on the channel the bathroom waste could pass across it and flow upstream towards IP1 and then stop in the pipe, eventually causing a blockage.


That's just a guess though, if the other manhole is buried at the same depth you could find it with a shovel or metal rod of some kind.

 

[Hugh Jaleak]

You really need to locate all the chambers, and get an accurate idea of what's going where firstly. Once thats done, I'd CCTV any pipework under the property to ascertain it's condition, and look for any obvious defects.

There are 'no-dig' options available where practical, lining and/or patching can be done from existing chambers to provide a structural repair to damaged, and even collapsed pipework, subject to survey and situation. Excavation would be a last resort I think.

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?

 

[KenGMac]

Foolish, Good evening again.

As regards your insurer and there "Passing the buck to the Water Board??"

Suggest you get back on to them, explain that your underfloor is contaminated with you do not know what? and you need them to clear it all out, after all your health is at risk?? and if the leak is ongoing it could??? lead to Subsidence ???

if you still hit, shall I call it resistance from the handler you talk to, simply say.

I am making a formal statement of "dissatisfaction with your handling of my claim", that is "I am making a formal complaint." because, there is contamination under the floor of my house that may affect my health? [ both the phrases above in " " are trigger words within the Insurance industry and certain actions MUST be taken by the handler accepting the call]

At this stage the Insurance handler will be forced by Insurance Rules to pass the Complaint to a dedicated Complaints team, this will bog you down for some time, one way around this to tell the complaints handler you are talking to that you want to to make a CEO complaint, and guess what the CEO does not want to hear about such things as a Complaint??

In effect make some waves, the Insurer is not infallible and remember the insurer will at ALL TIMES attempt to keep costs to a minimum, in effect the insurer operates a wearing down process, hoping that either the complainant goes away, or will accept any crumbs the Insurance company grants.

It may well be worth starting to play hard ball with your Insurer after all there is Go-Compare to fall back on after this is all over??

Ken