Slow draining toilet

A slow draining toilet flushes weakly, leaves the pan filling for longer than usual or only partly clears solid waste before the water level rises again. The cause is typically a partial blockage somewhere between the pan trap and the main drain, often involving wet wipes, sanitary products, excessive paper or a build-up in the soil branch. In older North London terraces with original cast iron stacks, internal corrosion and scaling can also reduce effective bore. Building Regulations Part H1 specifies 100mm minimum diameter for WC branches with a maximum length and gradient to maintain flow. Engineers usually inspect the trap and stack before rodding or jetting the soil pipe. If multiple toilets in the property are affected, the issue is likely in the underground drain rather than the fitting itself.