On Jan 26, 8:26*pm, "Bob M." wrote:
What causes a toilet to lose some of it's water in the bowl? *After flushing
it, it fills up just fine. When it stops filling, within 30 seconds the
water level in the bowl drops a bit (maybe 3/4") and stays there forever.
No leaks, two-piece toilet.

The flapper or ball that raises when you flush the toilet is bad. It
wastes alot of water when bad.