Toilet Blocking

[robertedjones]

Hello,

I'm seeking advice on resolving the persistent blockage issues with my downstairs toilet. A year ago, I replaced an 80s close-coupled toilet with a more affordable model. This new toilet is a back-to-wall type featuring a concealed cistern within a separate unit. Since its installation, I've encountered intermittent drainage problems. The toilet drains slowly, struggles to clear all paper waste (following Thames Water's advice, solid waste is no longer disposed of in this toilet), and occasionally becomes completely blocked. I've noticed that after being away for a week, the toilet functions correctly for a few days before the issues reappear.

Thames Water inspected the situation and informed me that the nearly horizontal pipe under the house, which connects to the main drain, is prone to blockages. I suspect my previous toilet, with its larger flush capacity and possibly more efficient pan design, didn't have this issue. The new toilet's pan, lacking a smooth U-bend and featuring a flat ceramic section – a trait I've learned is common in less expensive toilets made in China – might be contributing to the problem. The installing plumber suggested upgrading to a higher-quality cistern, like a Thomas Dudley model.

I'm considering purchasing a 9-litre Thomas Dudley Mirage Concealed Low-Level Cistern (link) and installing it as high as possible beneath the window, coupled with a new pan that has a more effective U-bend. However, I'm uncertain about which pans are of high quality and suitable for this setup. A local plumber's merchant was hesitant to recommend any specific cistern or toilet, believing it wouldn't resolve the issue and could be a waste of time and money. Yet, I'm convinced that the current toilet's flushing power is significantly weaker compared to others I've seen, and I'm running out of alternatives.

Could anyone offer suggestions on which toilet pan to choose or propose a better solution to this problem?

Thank you in advance for your help.

 

[robinbanks]

I didn't understand the part where you said you no longer dispose of solid waste (poop?) in this toilet? If you're only peeing in it then how is it blocking at all? If someone else is peeing in it and using half a roll of paper every time, a habit change might be needed..

..but are you sure that the soil pipe after the toilet is completely clear of blockages? Has it been camera'd all the way to the next manhole?

It would be a shame to spend a large amount of money chasing down a problem with a toilet that turns out to be some tree roots grown through an old clay pipe way out in the garden somewhere

ps; soil pipes are "nearly horizontal" by design. Too steep and the water rushes away leaving solids behind; a downward slope of 1 inch drop for every 80 inches is a typical minimum fall but in practical terms you'd find that soil pipes will still work even flatter than that, if something has settled and levelled it out more

 

[robertedjones]

Hi, thanks for your reply. I think the pipe is blocked a bit now yes, but Thames Water came out and unblocked it and used a camera. He said it is almost level so doesn't have much of a fall and would be advisable to only use it for wees, which we did but still gets blocked very easily. Unfortunately some people still use a small amount of toilet paper which often takes 2 flushes to get rid of. This problem has only come about since having the new toilet so assume the old style ones had enough a power to get it along the pipe.

 

[baldykev]

have you tried flushing the toilet with a bucket of water poured down the pan. Try that for a few days to see if that works
If it does you can try cutting back the volume of water used (ie 9 litres to 8 and so on) to see when it blocks up again on what volume of water.