Standing water inside tub drain

Question

I recently moved into a new home. One of the things I was getting around to doing was installing a hair catch for the bathtub, since there is no catch or drain stop installed. I purchased a universal hair catch at the hardware store and was about to install it, when I noticed there is standing water inside the drain. I then purchased a Drain Weasel tool to see if I could fish anything up, but to no avail; absolutely nothing comes up.

The water drains completely fine when the shower is running. If the spout is running, it is a little slower to drain. Here are a couple pictures for reference.

I find it interesting that the water doesn't get insanely backed up when I'm in the shower, yet this standing water never seems to drain. Is there possibly a clog somewhere deeper in the drain? Probably a job for the plumber? For the record, I live in a planned unit development.

Answer 1

That is just the water that's on the other side of the trap that's in place to keep sewer gas from coming up through the drain. Some traps are further away from the drains so you might not notice it but if the trap is located right under the drain, standing water will be there. When the spout is running it will disrupt the water flowing down the drain just because of the forced flow of water, that's normal. It's a great idea to install those hair catchers.