Where is it leaking from? The bearing seal or the cover plate?
If its the bearing seal then you need to replace the bearing and the seal. Chances are good the bearing is shot.
If it is the face plate then I would not worry about a slow leak like that in the short term. water
pump">Raw water pump housings are pretty corrosion
Even if a small groove were to appear along the sealing surface, a little silicone sealant
put on a new gasket would take care of that.
Some pumps use O-rings for the cover plate where you don't need to worry about a gasket.