I have a drainage problem in the bathroom.
So, after a bath, I drain the bath water into the bath sinkhole. But most of the bath water comes out of the shower sinkhole, flooding the shower and onto the bathroom floor!
Moreover, when I have a shower, the water floods quickly and it takes a very long time to drain!
I have taken photos, annotated, and attached them here. I hope the photos will help give you some idea of the drainage system.
I've tried clearing the blockage using a very long metal cable with a hook at the end (see attached), but this finds nothing and also it eventually hits something very solid and can't go any further (judging by the length, I think it's at the beginning of the piping outdoor - i.e., at the point where it exits the wall).
So, I suspect there's a lot of blockage in the piping outdoor (see the outdoor photo) rather than indoor.
right now, how can I remove blockage I think is in the outdoor piping? If you look at the outdoor photo, you'll see there's a cap at one end, that I'd like to try and take out. This I couldn't do as it seemed to be glued in. Do I need to try and turn it harder? Then should I use the metal cable with hook to try and find blockage through this end along the outdoor wall?
what short term & long term, inexpensive & expensive solutions can you see to ensure there'll be no more blockage?
a plumber we've been using has recommended creating a separate piping from shower all the way to the "soil pipe about 8 metres from shower" (I think that means to the very end of the piping outdoor) and quoted £350 for the work. I'm not convinced this would have stopped the blockage. Plus, the outdoor piping is actually only 3 months old. Very odd that it could block up so quickly. What do you think?
UPDATE: another point I should share is that when I run the bath and keep the drain opens, the running water goes out ok without flooding the shower. It's only when I fill up the bath and then drain it when it floods the shower. I'm guessing this is because of a) the pressure a full bath has on the drainage system, b) the blockage isn't 100% - more like 90%.
I will really, really appreciate any comments and/or answers you may have. :-)
With many thanks,