Hot Water Heater Periodic Leaking

I have a Reliance hot water heater. On an occasional basis I find a a fair amount of water around it. I cant determine where it is coming from however It seems as if it woul be the pressure relieve valve dumping water as I see no other constant leaking. Would the pressure relieve valve be dumping water on a periodic basis and for what reason? Or should I look for the mysterious water some place else.Bret