05/06/2026
Most people don’t give their drains a second thought... until the toilet won’t flush or sewage starts backing up.
This diagram shows how a typical house drainage system works and why the correct pipe fall is so important. Every pipe needs the right gradient so waste can flow away properly by gravity.
This will also help you understand why sewage sometimes comes up in the shower tray, bath, or even a downstairs toilet when the drains become blocked. When wastewater can’t get past a blockage, it looks for the next lowest outlet and starts backing up into the property.
A lot of the drainage issues we attend could have been avoided if the system was installed correctly or maintained before problems developed.
Have a look through the diagram and save it for future reference. You never know when this information might save you a costly call-out.
Got a drainage question? Drop it in the comments and we’ll do our best to answer it.
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