I have a strange toilet mystery here: my toilet flushes great if it has just
been flushed. However, the flush gets progressively worse as it sits without
being flushed. Let it sit for 20 mins, the water in the bowl only makes it
to an inch over the top of the drain hole. Let it sit overnight, and the
water in the bowl barely goes down halfway. The next flush (and any flushes
in close succession) will be perfect.
I first suspected some kind of leak, but can't find any. The water levels in
the bowl and the tank do not go down at all throughout these periods.
Any other ideas? I'm stumped.