How to Fix a Leaking Toilet (UK DIY Guide)
A leaking toilet can cause water damage, unpleasant smells and increased water bills. Leaks commonly occur at the base of the toilet, from the cistern, or from the water supply pipe.
This step-by-step UK DIY guide explains how to identify and fix a leaking toilet safely and when professional help is required.
Tools You’ll Need
- Adjustable spanner
- Screwdriver
- Replacement washers or seals
- Replacement fill valve (if required)
- Towels or cloths
- Small bucket
Step 1: Identify Where the Leak Is Coming From
Check carefully for signs of water around:
- The base of the toilet
- The cistern
- The water supply pipe
- The flush button or handle
Dry the area with a cloth and monitor to pinpoint the leak source.
Step 2: Fix a Leaking Cistern
Turn off the water supply using the isolation valve.
Remove the cistern lid.
Inspect the internal seals and washers.
Tighten any loose bolts carefully.
Replace worn rubber washers or seals if necessary.
Turn the water back on and test.
Step 3: Fix a Leak at the Toilet Base
Water pooling at the base may indicate a failed wax ring or pan connector seal.
Turn off the water supply.
Flush to empty the cistern.
If the seal is damaged, the toilet may need to be lifted and the seal replaced.
This is more complex and may require professional help.
Step 4: Fix a Leaking Water Supply Pipe
Check the pipe connection at the bottom of the cistern.
Tighten gently with a spanner.
If leaking continues, replace the rubber washer inside the connector.
Step 5: Test the Repair
Turn the water back on slowly.
Flush the toilet.
Check all areas carefully for further leaks.
Common Mistakes to Avoid
- Overtightening plastic fittings
- Ignoring small drips
- Failing to isolate the water supply
- Reusing old worn washers
- Attempting to reseal without identifying the true source
Leaks can worsen quickly if ignored.
When to Call a Professional
You should seek professional help if:
- The toilet needs to be fully removed
- The floor beneath is damaged
- The leak continues after replacing seals
- There is significant water damage
- You cannot isolate the water supply
See our Toilet Repair Cost Guide for typical UK repair pricing.