Extension and drain issue

[InTheCludgie]

We are considering adding a single level extension to the back of our mid terrace to make the small kitchen into a kitchen/diner but there are two small drains less than a metre from the back wall (pic attached). Does anyone have an idea if these could be shared with the neighbours or private, or where I could find out this info? I've read a few threads on here that say moving shared drains can be a big hassle and expense.

As we also want to extend into the loft to create an extra bedroom (9 year old ds and 5 year old DS are sharing at present) and so potentially have a lot of messy and stressful work coming up, we are debating just moving house to get what we need instead. We feel the drain issue will be a factor in what we decide. Anyone have any ideas/suggestions?

Ok it's not letting me add a picture but the drain covers are about 30 x 15 cm in size if that helps?

Can you open the cover and look inside see where the pipes go? Then turn on taps flush loos etc and check which way the water comes

I can only get the cover off one of them and it's got water sitting in it, cant see any pipes. When I flush, run water etc nothing seems to happen

When you bought the house your solicitor would have done a water and drainage search and you would have been sent a copy (probably by email). If you have lost it ask your solicitor for another copy.

This usually shows how the drains run in relation to your house though sometimes records are incomplete. It is usual in terraces for the drains to come through the garden of the end terrace house then run along through everyone's back gardens parallel with the terrace.

Drainage search can be useful but generally they only show the main drains rather than the full network. Far better to get someone on site to take a look.
I expect you have found the surface water drain, which sounds like an issue as there should never be standing water in a drain. The other one will be the foul sewer where your toilets and taps go. The real question is do your neighbours toilet and taps go there too, likewise for the surface water.

For the cost of the loft conversion plus losing space from upstairs for a staircase, and the cost of a ktichen extension, assuming you are replacing the kitchen, would it not be cheaper to look at a more suitable house for your needs?

I have done a single storey kitchen extension plus a new kitchen.

Drains wise as john says there should not be standing water in your drain, there is probably a blockage. Does it smell foul? Can you get something to feel around with and see how many pipes enter it? You can google how to clear a drain and it may not be a pleasant experience (been there, done that due to badly thought out drains)

Moving drains can be costly, it may involve digging a trench in the garden to site the pipework and inspection cover. It may involve the water board inspecting it. Is your intended extension across part of the house or the whole back of the house? I only had to move the kitchen drain so from the back of the house the drain went sideways and down the path down the side of my house. My house is detatched.

Thank you for your replies. The extension will cover the whole of the back of my house. My neighbour has a conservatory which they had done years ago, they didnt have any drains needing resiting but the conservatory only covers part of the back. They have a drain in the same position (in relation to their house) as the one which I couldn't open.

Chunky I feel you may be right about all the expense, not to mention hassle, of all this work and feel it may be best just to look into moving to somewhere that already has the work done.

The neighbour has recommended speaking to a builder who lives over the back from us - he helped with their conservatory build so they trust his opinion - to get an idea of what we might be in for with extending so that's my job for today!

We’ve just had planning permission for a single storey extension all across the back of our house and had the same issue. We took the cover off the drains and established that it is a shared drain with neighbours. Our architect has made a build over application to the water company - he is handling everything and says it won’t be too much of a pain to move it. If you are approaching architects for plans you can mention this to them