Bathroom drainage plumbing causing blockages/leaks Drainage and wastage systems and plumbing help, advice and answers

[MattGeorge]

Hi all,

I have been having some issues with the plumbing of our shower room for years, and have decided now is the time to fix the problem rather than bodging solutions.

The waste pipe for the shower and sink are flat to the floor and run around half the room before going down the soil pipe, so there is no chance for gravity to help.
I have attached a diagram to try to help illustrate the issue - the yellow pipes are all horizontal and either hidden under the shower tray or boxed in above the floor, so I can sort of access under the shower tray and behind the sink, but to access the rest I would need to rip out the boxing.

The toilet and sink are fine as the toilet is right next to the soil pipe and the sink is obviously up higher, but the shower really struggles to drain.
I have replaced the trap under the shower and all the pipe/fittings on that side of the room, but there is so little space under the shower tray that I could only find 2 or 3 traps on the market that would fit - so no chance of using one of those fast flow ones.
Once the shower has been running for around 5 minutes the water level will reach the top of the shower tray and then leak over the edge.

I'm not really sure how to solve this. We considered moving everything around, but due to the size of the room and there being a window, the only way to get the shower closer to the soil pipe would be to block the window.

Another thing I figured might help would be a pump - I found these sorts of things online that I could plumb the shower and sink to, but I don't have any experience here so would appreciate any input

https://www.anchorpumps.com/saniflo-san ... CyEALw_wcB

Apologies for the long post, but I felt I should give as much detail as possible.

[stoneyboy]

Hi mattgeorge,
Suggest you pressure clean the waste pipe through to the soil connection. If this doesn't work try fitting the shower on a plinth base which may solve the problem. Otherwise you could try your grey water pump but I think this has to be in an enclosure and you may not have the space.
Regards S

[MattGeorge]

Hi mattgeorge,
Suggest you pressure clean the waste pipe through to the soil connection. If this doesn't work try fitting the shower on a plinth base which may solve the problem. Otherwise you could try your grey water pump but I think this has to be in an enclosure and you may not have the space.
Regards S

Hi stoneyboy, thanks for your reply!

I have tried to clean the drain a few times, often resulting in a tiny improvement in flow rate for a few days. Yesterday I put a drain snake from the T join where the sink connects through to the soil pipe and it came out clean, but I'm assuming the pressure washing would be more for removing the sludge on the walls of the pipe etc?

I'm just hesitant about investing in the equipment necessary to pressure wash as this will be a rental property in the future and as the pipes are completely horizontal I'm assuming they will sludge up quicker - My thought was that a higher flow rate from having a pump would help mitigate the need for regular cleaning, although I appreciate that the pump itself may need more maintenance than just cleaning the pipes.

With the plinth suggestion are you talking about raising the shower tray up to give gravity a bit of a hand? I was thinking about this but I'm worried about damaging something in the process. Although if I find out that these pumps aren't worth the hassle then I can always get a professional in!

[stoneyboy]

Hi mattgeorge,
Yes raising the tray would allow you to utilise the extra fall even if you only raised up the accessible end of the 2m pipe run. This would also be self cleaning and maintenance free.
If you go the pump route you will have to get a registered sparky in to do the electrics and these pumps are far from silent.
Regards S