Pouring water on a grease fire is almost as bad as pouring gasoline on it. The problem is that the water turns to steam and the steam cloud carries the burning droplets of grease in the cloud which will spread it everywhere the cloud goes, It basically turns it into a napalm fire. The only way to use water effectively on a grease fire is with a high pressure water hose with a fog pattern or a foam nozzle. Grease fires can be extinguished with large amounts of water but usually there isn't enough water available to put out most typical grease fires in a house or restaurant. It would be more practical to have a special fire extinguisher on hand.
