Because there is a hole in it.
Believe it or not, water pumps can leak intermittently. If you can see it leaking there, replace the water pump.
water pumps have a seap hole that will leak when they go bad ,visually inspect this first
Most water pumps leak from the "Weep Hole" This means the seal on the shaft has failed and the coolant is running through the bearing. Alot of pumps fail the seal because the bearing is loose and wobbly.
YES
Evaporation.
You have to replace it. They are designed to leak when they are going bad.
Yes, if there is internal leak.
Water is a by product of the combustion and is normal.
air conditioner condensation drips
Do you have an exhaust leak? Do you happen to have have an exhaust leak or a damaged water pump bearing?
it pumps the antifreze through the rad.
Water pumps generally last 60,000 to 90,000 miles. They are usually replaced around the time that timing belts are replaced.