I don't think you need to worry about fuel pressure either, but just so you know,on the aft hose of the fuel filter there is a valve. It's just like a tire valve. Undo the cap, and push down on the pin, that will relieve fuel pressure and dribble fuel down your arm into your armpit if you don't put a rag under it.

I didn't relieve the fuel pressure when I pulled the fuel rail, and that would have made sense.

If you really feel like relieving fuel pressure, pull the fuel pump fuse and start the car. Once it stops running, you know you have no fuel pressure.

I'd say just change the water pump.