John and Al are worng - Sorry guys. Well, maybe I'm wrong and your right.
Well, anyway.

The key statement in the OP is "When I turn off the water, the leaking
stop".

That would indicate that the leak is somewhere between the washer on the
shutoff valve and the stop washer on the fill valve. My first thought was it
could be the packing nut on the shutoff valve.

Now that I re-read the OP and the other posts I think I'm probably wrong.

OK - So why can it leak at the connection from the supply line to the toilet
fill valve. Here is a thought - If you use one of those hard metal, chrome,
supply tubes. They can be a real pain to get alighned correctly. If thats
what the OP used for a replacement may I suggest one of the metal braided
flex lines with a built in washer on each end? Then no compression fittings
and less likely for leaks there. If it still leaks then its probably the
washer at the bottom of the fill valve. Or even the washer between the tank
a bowl.

wrote in message
ups.com...
I just realize my toilet is leaking at the connection of supply line to
the toilet. I've replaced the supply line but it's still leaking. I
don't think is the filling valve but I'm no plumber and a first time
home owner. When I turn off the water, the leaking stop, so the water
is not coing from the filled toilet, could it be the nut where the
supply line connecting to the toilet? Any advice will be helpful.
Thanks.