Out of nowhere, the water level in the bowl in one of our toilets is filling to about 3-4 inches below where it used to. It flushes normally and the innards seem to be working fine (though the flap is dropping back down pretty fast, perhaps faster than it used to), but the level of the clean water in the bowl after flushing is noticeably less than before. Not a huge problem, but I'm left wonder why. Any ideas?
Mike