Building Over 900mm surface water drain

I am in the process of applying for planning permission to build a two story extension on the side of my house. I have found out now i have applied and had the drawings done that according to Seven Trent i have a 900mm surface drain approx 7 meters down in the location of the proposed extension.
Seven Trent cannot confirm its actually there or whether its active but there official line is there records show its there and i must prove otherwise to be able to build within 5 meters of it ( my house must be within 5 meters).
Can anybody advise of my next step if there is one or does anyone know if it is there a way of building over the pipe?

You will have to get permission from ST, and for a 900mm sewer, I have my doubts they will give it.

When you apply for Building Control approval, they will refer you to ST and ST will send you out an application pack. You will have to submit detailed drawings of the extension (normally your bregs drawings) for them to consider. You will pay a fee to ST and they will insist that you have a CCTV drain survey done to locate the sewer, and determine the condition of the sewer. They may also insist on you having one done afterwards, to prove that your work has not damaged the sewer. Only their 'approved' contractors can do the CCTV survey.

If they are happy, then they will tell you and building control. Building control will not approve your plans unless ST agree.

It is actually a big, money-making scam by ST and the other authorities, as it allows them to update their records at no cost to them.

I've had many plans held up where ST have said their are sewers in the vacinity, but weeks and money down the line, the sewers are no-where near. They will refund your application fee if the sewers are not there, but not the CCTV fee, not the wasted time.

You may be able to get an engineer to design suitable foundations, but unless ST are happy that your extension will not affect the pipe, nor prevent any possible future access, then they will not approve the work.

BTW, who ever did the drawings should have advised you of all this, and not let you find out afterwards

Woody thanks for the info you obviously have a lot of experience in this area.
Is it worth pursuing? or am i throwing good money away having all ready forked out for drawings and planning permission.
I have a ST drawing that shows the pipe coming through but my builder tells me it may not be there at all?
I don't mind spending the money if the outcome is i can go ahead with the build, i just don't want to spend anymore to find there is no way i can build.

Well, if you have already spent a lot on this, I don't see why you can't spend a bit more and make the application to ST - yes there is the possiblility of the pipe not being there, and there is the possible approval and so you can build the extension.

You have a lot to gain, so I would go for it.

The only bummer is that you are looking at a fee of initially £256, but as the sewer is over 300mm, you will be charged "at cost" - so you need to find out a likely fee. ST will refund 50% if it is refused.

CCTV will be about £200, and you can only use their 'approved' contractors

Woody many thanks your advise has been very useful