How to Fix Toilet Leaking Into Bowl

Water is constantly trickling into the bowl, even when the toilet hasn’t been used.

Is this your problem?

What to do

1. Lift the cistern lid carefully.
2. Look at the water level — if it’s too high and spilling into the overflow pipe, that’s the issue.
3. Find the float (a ball or cup on an arm).
4. Adjust it down slightly:
   • On older toilets: bend the metal arm gently downward.
   • On newer ones: use the adjustment screw or clip.
5. Flush and check if the water stops rising too high.

Safe DIY: Yes.
Stop if: parts feel brittle or you see cracks — fittings can snap easily.

Water leaks into the bowl from the bottom, even though the water level looks normal.

Is this your problem?

What to do

1. Turn off the water supply (usually a small valve on the pipe behind or below the cistern).
2. Flush to empty the cistern.
3. At the bottom inside, you’ll see the flush valve with a rubber seal (called a flapper or washer).
4. Check if the rubber is worn, warped, or covered in limescale.
5. Clean it with warm water and a cloth first.
6. If damaged, replace the seal — these are inexpensive and widely available in the UK (e.g. Fluidmaster or Dudley parts).

Safe DIY: Yes, if you’re comfortable removing and refitting parts.
Stop if: the valve doesn’t come apart easily — forcing it can break the unit.

The toilet only leaks after flushing and then keeps running.

Is this your problem?

What to do

1. Check the chain or push-button mechanism.
2. Make sure the chain isn’t too tight or tangled — it should have a little slack.
3. Ensure the flush valve fully drops back into place after flushing.
4. If it sticks, clean around the valve housing — limescale is common in UK hard water areas.

Safe DIY: Yes.
Stop if: internal parts feel stiff or jammed — may need replacement.

You hear occasional refilling (every few minutes), but no obvious constant flow.

Is this your problem?

What to do

1. Add a few drops of food colouring into the cistern water.
2. Wait 10–15 minutes without flushing.
3. If colour appears in the bowl, there’s a slow leak through the valve seal.
4. Replace the washer or flush valve seal.

Safe DIY: Yes.
Stop if: you’re unsure which replacement part fits — take a photo and match it at a local plumbing merchant (Screwfix/Toolstation).

The cistern is old and parts look worn, scaled, or mismatched.

The cistern is old and parts look worn, scaled, or mismatched.

Is this your problem?

What to do

1. Consider replacing the full flush valve or fill valve kit.
2. Modern kits are cheap, quieter, and more water-efficient.
3. Turn off water, drain cistern, and swap components following instructions.

Safe DIY: Only if you’re confident with basic plumbing.
Call a plumber if:

• You can’t isolate the water supply
• There are leaks outside the toilet
• Bolts or seals underneath the cistern are involved