Every have that leaky faucet that just won't shut off? What if it becomes a steady stream, or even a gusher? You'll need to shut off the water suppy, and it may be that you have to get it shut off quickly. An emergency has just occurred. Next question, where do I find the shut off? Some may think the shut off is outside, at the point of entry for the water main. More than likely, though, it's directly below the sink, in the cabinet. Behind those cleansers and towels. When you have time, take a look below your sink and see if your situation is similar to the picture here. If correct, hot should be on left and cold on the right. The shuts offs work like screws and bolts, or "righty tighty and lefty loosy". Turn to the right to shut off, and left to turn on. To be safe, know where your shut offs are before an emergency catches you unaware. When the water is safely shut off, then you'll have time to assess your situation.