Often times a pump will leak or spray water affluent to the intake after water has become pressurized. Usually this can be explained by cracked or deformed components, o-rings, or a bad mechanical shaft seal. When water is pouring out behind seal plate where the shaft enters the housing it indicates a worn mechanical shaft seal and is need of replacement. A common leak on a pool pump is the connection on the return side.The seal has to be replaced once in 03 years. If not, it will leak inside and damage the bearing, Impeller and Housing. This photo shows a Hayward pool motor leak. The result was a seized bearing and or motor.