Damp appearing on exterior wall behind toilet fixture Drainage and wastage systems and plumbing help, advice and answers

[Gray_notts]

Hi,
A damp area has appeared on an exterior wall directly behind a toilet fixture. No damp on the interior wall or toilet.
Please see image. Could it be a leak on the waste from the toilet? Or a leak on the mains pipe on the toilet file?
Grateful for any help.
thanks

[stoneyboy]

Hi gray_notts,
Since you have cavity walls it is unlikely that the inside skin will be dry and the outer damp. Is there another overflow at a higher level directly above the damp patch?
Regards S

[Gray_notts]

Hi,
No, no other overflow or water source above above this spot.
It's roughly inline with the toilet waste pipe so may it is a leak there when toilet is flushed? We've stopped using it to see if damp recides.
thanks

[LorraimeGee]

Hi.
Just seen your post as i was looking for an answer to the exact same problem!

Would you mind letting me know if you found the source of your damp wall please?

Thank you.