I've recently moved into a 1980's Top Floor flat/apartment. There is an issue with the Toilet. It flushes perfectly, and does the job as expected. However, when returning after couple of hours later, I've noticed that there is a nasty brown thick sludge that is slowly making its way back down the from the back trap. After the trap, the soil pipe doesn't go straight down, but instead goes back, and descends about 25 degs from horizontal. After a day or so, of not flushing, the toilet bowl looks like you might expect if someone 'forgot' to flush after a long visit. In this case flushing doesn't always work. What is causing this and how can it be fixed? Please help…

Are you the only unit on the top floor or are there others? Back to you, Tom

Hi Speedball1,

There are 9 other top floor flats, each of which are Maisonettes (over 2 floors). The toilet is on the first (top)floor, and soil pipe goes straight down, through the lower (ground) floor, and then continues down where it is shared with the flats below. So, in my case the soil pipe isn't shared horizontally, but is shared vertically when it leaves my flat. Thanks, Tom

Are you in the UK? Does your wall back up to another units bathroom? You're getting another units discharge backed up in your toilet. Are these rented units? Do you have as maintenance depart in your building? Did this just start or has it been a ongoing problem? Back to you, Tom

Hey again,

Thanks for your questions, hopefully my answers will be useful...

- Yes, I'm base in London, UK.
- No, the toilet is in a separate room.
- All other bathroom, kitchen, laundry units are fine.
- I am the new owner (Leaseholder) of the flat. The local council are the Freeholders of the building, that the flat is in.
- I don't think there is a maintenance department, but will check.
- It's been a problem since I moved in mid-Dec 2011. Initially, I thought my girlfriend had forgot to flush, but was surprised because she's tiny, and the thing was/is huge. It look a little like a sea-slug: http://www.bing.com/images/search?q=sea+slugs+types&view=detail&id=9A975C899DE89BAD2F3EF24BA67AF0B11BB7DE46&first=0&FORM=IDFRIR

Thanks again! Tom