Well I have never heard of a water pump warnign indicator but if that is the case, I would say yoru water pump is going or has gone out. Take the cap off a COLD radiator and start the car up and let it idle. When your car reaches NORMAL operating temp see if there is any water flowing or moving in the radiator. Just peer in the hole and see if there is any movement. If the temp goes above normal and starts to get hot and no water is moving it's either the thermostat is stuck or your water pump is out. Don't keep driving the engien hot otherwise you will blow a head gasket or worse.