I’m looking to put a single story extension on a semi detached house under the permitted development. I want to go out as far as I’m allowed, without planning permission it’s 3m but the problem I have is the drainage. This runs along the back gardens and is exactly 3m away from the house. Has anyone had this and what did you do? I don’t want the extension to be smaller, if anything I’d prefer it bigger and wouldn’t mind applying for permission if I knew they’d allow it. The drainage runs parallel with the house so would relocating it further out be an option? I’m awaiting someone coming to look at this I was just wondering for the time being. Thanks!