Plumbing and maintenance
A toilet that keeps running: the three usual causes
The practical points
- 1
A worn flush valve seal lets water pass from cistern to pan continuously; you can usually see the ripple on the pan water.
- 2
A fill valve set too high pushes water into the internal overflow, which looks like a leak but is a level adjustment.
Before you commit
A fill valve set too high pushes water into the internal overflow, which looks like a leak but is a level adjustment.
Frequently asked
How do I test it?
Put a little food colouring in the cistern; if colour appears in the pan without flushing, the flush valve is passing.
Can I just replace the whole mechanism?
Often the simplest fix, especially in older cisterns where parts are no longer matched.
Working out what is realistic in your space?
Room dimensions, the position of the window and where the waste leaves the building decide most of it. Send those and we can be specific.