Inside the tank
Running, refilling and handle trouble
A toilet that keeps running or refills when nobody has used it may be letting water pass from the tank into the bowl, sometimes called ghost flushing. The sound is a clue rather than a diagnosis, because several internal parts can cause it.
The fix might be a new flapper, fill valve, flush valve or handle, or a fresh seal between tank and bowl, depending on what failed. Mention when you hear the water running and whether it stops by itself; the technician checks the parts before swapping anything out.
