found a drain pipe in garden and overflowing

[OrangeJuice09]

Hi,

My normal drain is at the head and knowing this I dug up the patio to build an extension. However, I found another pipe that was terminated at the border, but as i dug round it the soil became loose and the pipe opened.
Sometime soapy water comes out and starts to flood my foundation. I looked down the pipe and it seems that the pipe goes downwards so, its backfilling and overflowing.
It seems to be a lateral drain and the neighbour said that its the old drain pipe thats been replaced with a new one.

I called Severn Trent and they sent a team to investigate. The 1st team didn't make any notes on their report about this (unused) drain. So I asked ST to take another look, they sent another team and upon inspection they took photos and told me that I can concrete it up, though I told them that water occasionally comes out. I managed to get something in writing but it only states that its a private unused pipe pipe and not on their map.

I dont understand why ST are saying its a private pipe, they say its not on their map, but surly they must have laid this pipe and their maps are out dated ?

I think someone has plugged a washing machine into this pipe and their end is somewhat blocked and pushes back into my garden. The pressure is low, and I believe it slowly drains away back down the pipe. If I concrete it up (it was terminated in the first place for 20 years+) will this become an issue ?
Also is concrete waterproof ?

Any advice would help.

 

[CBW]

Why are you under the impression that Severn Trent laid it? One way to start tracing that is using some drain dye, another would be to keep digging. Not sure if someone like @Hugh Jaleak will know any different?

 

[Hugh Jaleak]

Firstly, how old is the property? Sewer maps are also only a guide, they often show the rough position of a sewer but are not an exact science, further investigation on site usually determines the exact route. Maps also depend on the quality and availability of drawings from the time the sewers were laid, some places can have amazing, detailed works from 100 years ago, something built in the 70's may have nothing, so the network would have been surveyed at some point and maps drawn.

Secondly, they often only show the bigger runs, (6" and above), to plot every 4" run, often just taking 1 or 2 properties, would be very labourious, and isn't really necessary. Private runs are not the Utility Company's responsibility so they are not going to waste resources mapping these.

As Chris rightly says, why do you think ST laid it? Sewers are usually laid by the Builders, the only time the Water Co's get involved is to lay new sewers to upgrade the network.