Not very often.Usually when water valves fail they stay failed. they don't fix themselves. Water valves consist of a spring loaded plunger that is always having pressure applied to it by PSI on the water line. When water is called for a solenoid yanks open the plunger and as soon as power is removed water pressure is shoving against the already spring loaded plunger. I have seen em get stuck open from calcium and lime buildup but that was RARE. Usually they come to a trickle and take fifty forevers to fill the washer before they become permanently open and even then they dribble like a faucet leak. One just pouring out water seems to me like is an impossibility from what I have seen at my appliance parts store over the years when I was in the biz.