How do I know if a drain is a soakaway or not?

[fathertobe]

Hi,
Live in a property built in 1850 which is semi detached.
At the front, there is a trench in front of the lower ground window and at one end of this there is a grate (serving both my neighbour and my property) as a rainwater drainoff.

Is there any easy way of telling whether this is a soakaway or connects to the main system?

LIfting the manhole (down the side of the path) doesn't provide any clues - water runs from back to front of the property and the rainwater drain is further forward in the property.

Please help!

 

[Agile]

Thats even older than mine which is 1860 !

As far as I can deduce mine was built without any fixed toilet and is just two up and two down with no plumbing or lighting originally. A rear extension was built sometime, probably during 1926 when the adjoining house was built and both houses share the soil drain. Most of the other houses in the immediate area were built during the 1930s but the main drain under the road was presumably there during 1926 when the second house was built.

So in your case its difficult for me to guess but it all depends on the local infrastructure at the btime it was built.

I cannot think of any way for you to test it short of CTV down the drain to see if there are any branches joining it.

Tony

 

[fatplumber]

Try plan registry. They will have most drainage marked.

 

[fathertobe]

Plan registry?

Does that mean planning and registry? I checked with Thames Water drawings but they just show public sewer.

 

[fathertobe]

Gawd ... this gets worse. To get a CCTV camera down there, they have to dig out the gulley.

 

[Agile]

I think he means Building Control.

In the case of our office address built in the 1890s all they had was a typical arrangement although it was useful to me because it showed that it was a running trap ( if thats what they are called ).

Doitall probably remembers them, a vertical pipe going down about 200 mm and then a "U" shape at the bottom and then a "P" outlet which is totally inaccessable.

It had actually blocked at the connection with the public sewer in the centre of the road. I would have liked to inspect that if the sewer is large enough to walk along but its probably only about 12-18" but it was a narrow street and a bus route so I did not try that. I unblocked it in the end using my power jetting pump.

Er...why do you need to know where it goes to?

Tony

 

[fathertobe]

Hi Tony,

Thanks for helping.

In fact you've been here ... and to my previous address! Do you remember? De Beauvoir.

We've moved the kitchen to the front of the house and after considering all the problems, everyone failed to overlook the fact that the outside drain (running in a trench in front of the lower ground floor window) is possibly just a soakaway rather than leading to the (combined) sewer. At the time there was more obsession about storm/foul systems.

And if it is indeed a soakaway, this rather scuppers our plans for the kitchen waste ... And is going to be a MAJOR pain...

 

[Agile]

Yes, of course! But then I was looking at boiler options. Nor did I realise it was so old.

There is always an option to run the drains under the floor to the back of the house presumably?

In the worst case they could be pumped too.

With that kind of house I would have expected that it will be taken to the main drain as the whole street was presumably developed at the same time. My 1860 cottage was the only house for about 1/4 mile when it was built.

Tony

 

[fathertobe]

Hi,

1 Running it the length of the house under the floor will be tricky...
2 Getting it around the front of the house will require some serious digging.

So ... I'm praying you're right and it isn't a soakaway...

Just a thought ... wonder if you could go with a CCTV camera up from the main inspection hatch (towards the road) and then possibly detect a branch left (that would indicate it leads to the drain in question).

 

[fatplumber]

+Honestly building control and plan registry are your best bet.

 

[fathertobe]

Building Control are useless and I'm afraid I don't know what you mean by 'plan registry'.

I'm going to arrange for a CCTV inspection - which will involve breaking the clay drain, I imagine. Here's to £300 to find out something I don't want to know ...

 

[Agile]

If you can make or get a CCTV then its easy to run a hose into the drain in question and the water will be clearly seen and then it can be turned off to confirm.

Tony

 

[fathertobe]

I can't really get a CCTV thing together myself and hire won't be much cheaper.

I'll let you know the outcome. Thanks for your support, Tony. May be in touch soon on a boiler servicing issue if you're willing ...

 

[fatplumber]

All plans submitted are kept in the local authority plan registry. If you live in central London then it is unlikely that your drain is a soakaway. The other authority that will probably be able to help you is the water undertaking. I have had to call on Thames Water several times. If you have joint drainage with a neighbour then the water company is responsible for your drains from the junction. They usually have some record. They should also arrange a visit to ascertain as to whose responsibility it is.

 

[Hugh Jaleak]

May be worth speaking to the water people. Quickest and easiest way IMHO of ascertaining if this gulley is connected to a combined system would be to dye test it. You would need access to a manhole downstream of where this gulley could be connected to the main sewer though, and this sounds like it may have to be a manhole in the road. Pour a bucket of water containing drain tracing dye into the gulley, if it appears downstream in the (foul) sewer you have your answer!