89 firebird water pump leak

i have an 89 firebird with a 305 and i've been constantly filling it up with water for the last week cus i dont have the time to mess with it. well today i bought a new radiator cap cus the red tab release has been broken for a while. i bought a new regular cap and when i was filling it up with water(no antifreeze just incase there was a problem) i saw water coming out from the top of the water pump(hole on top) this is the first time i noticed it. what would cause that? i will replace it 2moro anyways just curious

Most water pumps have weep holes that will intentionally leak when the pump bearing starts to take a dump.