Bathroom drainage: bath's water flooding shower

Question

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.

Questions:

1. 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?

2. what short term & long term, inexpensive & expensive solutions can you see to ensure there'll be no more blockage?

3. 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,

Ben

Answer 1

Assuming this is a newly manifested problem in and otherwise regularly functional drain system, there are 2 things to do first:

1. Insert your snake into the plumbing system through the shower drain, not the tub (you will have less chance of coiling it up on itself) and measure how far it goes before it hits the hard stop. In case you don't understand, you want to have the snake be rotating the whole time you move it through the pipe. It's designed to auger its way along and create a spiral cutting action inside the pipe (If this is a manual snake, go and get a powered one or one that has a small shaft on it to be turned by a cordless drill). My first suspicion is that the hard stop you are feeling is the elbow on the outside wall where the bathroom drain plumbing exits the brick. If the auger stops at that distance, you can just keep pushing while rotating to get it around the elbow. Then you can see if you can clear anymore out of the pipe.

2. Since the above almost never works to get rid of a blockage like what you are describing, the next thing to do is remove the inspection cap. It's probably just cemented into place. Just cut it off in such a way that there is a small piece of pipe left for you to cement a new cap in when you are done. This time, install one with a removable clean out plug or cap. Once the cap is out, run your snake through the pipe as far as it will go and see if you can cut the clog out with the snake. Don't be afraid to run it for 10 or 15 minutes to grind away at the inside of the drain and remove all accretions.

It's hard to tell from the photos, but I don't think you have enough slope on any of your drain lines - they almost look level - and this can lead to accretions in various areas. That might explain why you are having issues. It may have been installed by a dummy. That could help to figure out why the problem is manifesting itself. It's common for tubs to exhibit clogs only when draining a filled tub as the rate of flow of water is highest then. You also might want to put some sealant around the pipes where they exit through the brick. Very unprofessional.

If these two steps don't work, then it's time to get a plumber. Get three quotes and pick the guy you like best - not the cheapest guy.

Answer 2

The answer given by @personal-privacy-advocate is fairly sound advice however I would add the following:

• "the above almost never works to get rid of a blockage" referring to drain cables/augers/snakes. This may be true for laypersons. Using these tools properly (without damaging the tool) and effectively (they nearly always work when wielded properly) takes experience and skill. I have found them very effective directly from the drain in question.