Survey - Drain running under old extension

[housie]

Our homebuyer survey has come back highlighting that the drain runs under the house extension (kitchen diner) from right to left, but there are no accessible inspection chambers.

Extension built in the 90s.

We’ve been asked to get a drainage search. CCTV etc to locate the inspection chamber.

I’m worried this poses a real risk in terms of possible collapsed drains in the future, or penalties due to no build over agreement.

Is this a common problem? If we get a drainage search and the drain looks ok for now, will that do? Would we get into trouble with the sewage board (?)

Or walk away? We are near the finish line...

What drain? Your own house grey water, or the sewage for the street?

I assumed it’s for the street ... if it runs across the plot from right boundary to left boundary. Not sure, I’m afraid. So a public sewer? 😰

A minor detail, but one which could avoid confusion later.... I think you may have said "drainage search" when you meant a "drainage survey"?

As I understood it a "search" is a paper exercise involving researching the records of the sewerage undertaker (in most parts of the country this means the same as "the water company"), whereas a "survey" involves someone actually looking at the drains on site.

Thank you @CasperGutman, I did mean survey!

A homebuyer survey isn’t always very thorough, so maybe ask the agent if the vendor has any evidence of the drain location before you decide next steps. (Verifying etc)
We were asked to do a build over agreement for our extension and if turned out the sewer was a 100m away. Admin error in our case, and in our case easily resolved.

You may be able to gain access from an inspection drain on your neighbours property, but it will of course depend in if they agree to it. What year was your house built? I would be more concerned if it’s an older property with Victorian style sewerage pipes and ironwork than l would on a 1990s house with the plastic type.

It’s fairly standard practice now to have a drainage survey done as part of Conveyancing procedure. We had to get one done that involved a Septic tank and digester plant inspection on the last place we sold.

It’s a 1950s semi. The vendor was the one who informed the surveyor re drain location running under the house. I presume the extension was built over it (in the 90s) before the law came in requiring the build over agreement... so they haven’t done anything illegal but I don’t know how this will affect us in the future.
If the drain belongs to the water board could they have the right to demolish the extension (?!) Sorry for the daft question - I clearly don’t know how this works. Hoping to talk to the solicitors tomorrow

DEFINITELY get a cctv survey to check it all out

I recently bought a house, was not aware extension built above a shared sewer (despite paying for a full building survey), am currently having various problems which will be expensive to fix. Tread carefully

Thank you for the advice @DespairingHomeowner and sorry to hear of the problems!
If you don’t mind me asking - was it something you think could have been caught via a CCTV survey?

Yes I do: will PM you