Toilet Won't Stop Running? Here's What's Actually Wrong
A running toilet can waste 200-400 litres a day. The three usual culprits, and which ones you can check yourself.
A leaking loo is the quietest expensive fault in the house — a continuously passing flush valve can waste 200-400 litres a day, more than a family of four typically uses.
The paper test
Dry the back of the pan above the waterline and stick a small square of toilet paper to it. Check back in ten minutes. Wet paper means water's trickling from the cistern into the pan.
Three usual causes
The flush valve seal — hardens with limescale over time, the most common fault in hard water areas.
The fill valve or float — if water's running into the overflow, the valve isn't shutting off or the float's set too high.
The flush button mechanism — dual-flush buttons stick partly depressed, holding the valve open; if it only runs after certain flushes, this is usually the culprit rather than the valve itself.
Concealed cisterns
If yours is behind tiling, repairs go through the flush plate aperture — worth getting someone experienced, since forcing a scaled valve out of a boxed frame is how tiles crack.