How to Fix a Toilet That Won't Flush

Overview

A toilet that won't flush can be caused by a broken flush mechanism or a blocked siphon. This guide covers fixing the issue.

Step-by-Step Fix

1. Carefully lift off the toilet cistern lid and place it safely to one side, away from the toilet bowl. Look inside the cistern to locate the flush handle arm and ensure it is properly connected to the flush button or lever on the outside of the cistern.
2. Once the lid is off, observe the small chain or wire connecting the handle arm to the rubber flapper or diaphragm at the bottom of the cistern. This chain should have a small amount of slack, roughly 1-2cm, allowing the flapper to fully drop and seal after flushing.
3. If you find that the chain is broken, detached, or missing, you will need to replace it. Purchase a new cistern chain from a DIY store, attach one end securely to the flush arm and the other to the flapper, ensuring the correct amount of slack.
4. Check if the rubber flapper or diaphragm at the bottom of the cistern is sealing properly against the flush valve opening. Give it a gentle press down to ensure it sits snugly; if it looks stiff, cracked, or doesn't drop back down correctly, it might be the cause.
5. If the flapper appears fine but the toilet still isn't flushing effectively, or if other parts of the flush mechanism (like the overflow pipe or fill valve) are visibly damaged, the entire flush mechanism might need replacing. This involves draining the cistern and installing a new complete flush valve assembly.

Common Symptoms & Diagnostic Resolutions

Review the common error codes and operating symptoms below to quickly identify the root cause of the fault before ordering replacement parts.

Frequently Asked Questions