2003 Pontiac Montana fluid leak from cooling system

Fluid keeps leaking out of cooling system, and I have had to refill radiator once per week for the last couple weeks. I beleive it is the water pump located on left side of engine that is leaking, but am not sure. When I have the engine running water seems to be getting on the belt because I can feel a small spray of liquid when I stick my face down in the engine compartment to try and see where the leak is. How could I make sure that it is the water pump and not a hose or even the radiator itself leaking?