In Fluent post-processing, there are several pressures that are outputted that are often confuse young (and even experienced) users. There should be a sticky post on the top of the board that should explain it (ANSYS are you "listening"). There are some short notes below, but if you do a search in the forum there are better descriptions.

Static Pressure - This is the pressure calculated by the solver. Keep in mind it is measured against to the operating pressure.

Absolute Pressure - This is the combination of the static and the operating pressure.

Total Pressure - This is the combination of the static and dynamic pressures.

CCF? That is a very good question. I should have typed CFF (Custom Field Function), sorry. This allows you to create user variables. Using this you could create a variable MyPressure that is the combination of the Absolute Pressure + rho g * Z. Again if you search the forums there probably are examples.

But above it sounds like do not have a fixed surface height. Then we have to measure Z against the water fluid interface. That leads to your good question of the free surface location, and that I would have to think about a bit. Are you using the VOF (Volume of Fluid) model?