I have found quite a few posts about smells from bathroom drainage but all appear to have the smell in the bathroom.
My problem is different in that the smell appears outside in the drain.
I know it is not the drain itself - I have checked that by running water into it from a hosepipe. We also do not get the smell when any of the kitchen waste is run into it.
The smell (like a really foul drain) only happens when the washbasin appears to be used or the shower. I have not noticed it when the bath empties.
The plumbing has been in place about 15 years but this smell has only started happening recently.
I thought at first that it was the outside drain but, as I said, this has now been ruled out.
There is no smell appearing in the bathroom itself.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!