Victorian sewers - advice needed

[usignuolo]

I live in a Victorian house in London. When I moved in, 20 years ago, s I had the plumbing redone. The council said there were no plans of the drains or sewers in the area.

My main soil stack is at the rear corner of my house (inside the conservatory). The main down rain water pipe from the roof is next to the soil stack. The plumber, unable to find a sewer trap near the main sewer, inserted the external down soil stack into the existing Victorian sewer and put an inspection chamber on the front of both pipes, near the ground.

Six years ago I had a conservatory built on the side of my house which now covers the corner with the soil and rainwater stacks. The conservatory floor was laid over the ground where the sewer runs out to the back garden, with a dpm etc. At the council's request, I had the drains rodded. They established the main sewer continued beyond the back of the house for around 200 yards going south. At that point everyone gave up searching.

My next door neighbour's soil stack, facing mine, is approximately 12 feet away (there is a wall between our houses). My neighbour does not have a conservatory, his soil stack is outside.

My neighbour had a new kitchen at the rear of his house recently when he also had a downstairs loo and shower installed. He has connected the sink waste outside into the main drains and also installed a rainwater ground drain for hosing his patio etc. There is no point in asking him where they all go and how they are connected. It's been tried, he just looks gormless and clams up.

He also has a large tree at the front of his house whose roots have stretched back along the path at the side of his house to the rear near the drains. When we found its roots lifting our side path as well we removed them but he said he didn't regard the roots on his side as a problem. He also refuses to have it pruned although he cannot see out of his window.

This week, for the first time since living here, my sewer down pipe blocked up and I had to get in Drain Master to clear it. He rodded down the trap in my sewer pipe and said the blockage was at a point about equi-distant between my house and my neighbours - roughly where I assume my drains meet my neighbours and join the main outflow. There was nothing "bulky or unsuitable" in my down pipe to have blocked it.

The questions I have are, does anyone know how victorian sewers were laid in this type of development? Is is likely that my soil stack and my neighbours lead to a communal trap between our houses where they join the main sewer going south. (The sewer seems to run under the rear gardens heading south but no one knows where it leads as there are no plans.)

If we share a common sewer pipe from a communal trap between our houses who is responsible for the trap getting blocked? If so, could my sewer pipes be blocked by my neighbour, depositing something down his side or would it inevitably affect both? (and vice versa).

I am concerned the problem is on his side not mine and would like some advice to approach him with before it occurs again.


Usignuolo

 

[ricarbo]

I'm struggling with your terminology a bit!
Normally, each house has it's own 4" drain, which goes to the property boundary (with manholes at every junction and every change of direction, laterally or because the fall of the drain varies). At the boundary there is a trap, called the interceptor, and that discharges into the council's sewer.
The system may be 'combined' where the foul and surface water both go into the sewer, or 'separate', where the foul water (any contact with humans) goes to the sewer and the surface water (from the gutters, no human contact) goes to a soakaway (big hole filled with hardcore). There is no trap at the bottom of the stack, but if foul water drainage e.g. a kichen waste, discharges above a gulley, that will have a trap.
It's not usual for two houses to share a drain, but not impossible. If so there should be a manhole (without traps) at the junction.
Tree roots in drains is very serious. Can cause the collapse of the house foundations.
Perhaps you should consider calling in a qualified building surveyor.

 

[JohnD]

these common sewers are quite common in older london houses where a row was built at the same time. There is a small sewer running behind several houses which eventually passes beside one of them and joins the main sewer in the road. There are seldom enough manholes or inspection covers. If they are old enough then, although they are privately owned, they were considered acceptable when built and Thames water or council will clear blockages FOC (though you have to pay for your own repairs). I had it done when I had one of these, the blockage being several houses away, but I had renewed soilpipes and traps in plastic so noticed it earlier than neighbours whose salt-glaze had cracked from wartime damage or clay subsidence (which was the reason I had replaced mine, found cracks and cavities when digging out for new patio)

The drain man was obviously used to sewers and I was quite entertained to see him sitting on the edge of the pit with his boots in the muck, a mug of tea in one gloved hand and a doughnut in the other.

 

[usignuolo]

Hi there

Thanks John D.

I spoke to Thames Water who looked up my property on their assets database. They have a record of a main sewer owned by them under the middle of the street but but no record at all of any connections into it. (Although there are Victorian houses on both sides).

They said this means that any connections to the sewer are private and all blockages and repairs up to and including connection to it are the responsibility of the owner. That includes finding out where the connections are.

I asked how I find out where my drain joins the main sewer, and was told to look in the manhole or inspection cover in my garden - only I don''t have one. When the conservatory was being built and the water supply was off, we did get someone to send a CCTV camera down it from the main stack inspection chamber. It ran off down the back garden and kept going until the camera ran out of cable, without ever coming to an end...no sign of it joining the main sewer in the road outside the house which is the opposite direction. (Maybe it emerges in another road several hundred yards away?)

The local Drains clearance man says said that in my neighbourhood, no one knows where the drains run and Thames Water washed its hands of the problem some time ago.

This was fine while the drains worked but now with so many mature trees near the houses the roots are getting into the old salt glaze pipes and cracking them. This in turn is causing subsidence.

It seems a pity that when someone has some work done on their drains there is not an obligation to record where the drains are, for future reference.

I wonder what would happen if an elderly person had a major blockage and could not afford to pay for it to be fixed. We already have one house recently vacated, with the drains collapsed into the sewer caused by a large tree and there are suspicions of more. If an OAP cannot pay and Thames Water doesn't want to know, then what happens?


Usignuolo

 

[JohnD]

What a pain!

I wonder if the drains are shown on the "deeds" - which will now have been dematerialised and put on the Land Registry computer, but they will send you a copy including coloured copies of the plan for a fee.

They may also say what are the responsibiltes of neighbors, which might be useful.

I think when I had mine cleared it might have been the borough council that helped, though I don't clearly remember. I was lucky enough not to have to pay.