How can I tell if I need to replace my water pump ?

I'm trying to do preventative maintenance on my car and I heard about vehicles coming to a dead stop when the water pump goes out. I definitely want to avoid that. What's a good way to test it?How can I tell if I need to replace my water pump ?Coolant Pressure tester is the best way. PM depends on the car. Some cars {Honda,Mitsu, Toyo}the water pump is driven by the timing belt. Best real world idea is to change it with the timing belt if that is the case.How can I tell if I need to replace my water pump ?hum. they usually leak (there is a hole under the boss that the shaft goes through to let water or coolant drain when the seal or bearing begins to go out) or rattle, buzz, squeak, or something. in short they let ya know when you are observant. don't replace it 'till you see something like this.How can I tell if I need to replace my water pump ?I dont think there really is a good way to test your water pump. My water pump went out during a trip to phoenix... first my friend and I heard this awfull squealing sound (the belt) by the time we got off the highway the belt was gone and the truck started sounding better... but when a mechanic came out to put a new belt on he noticed that my water pump wasnt moving anymore. I was lucky... I drove an older Toyota pickup so the actual pump only cost about $27. While the water pump was broken my truck still ran... we had to drive it to the mechanic. But it was near over heating in about 10 mins.