It is always good to know where the main water shutoff to your home is located and how to use it. Some homes have a shutoff valve within the structure, such as the basement, garage or utility closet. Others have one outside in the yard or near the water main in the street, curb or sidewalk. You can also consult a plumber during your next call and ask them to show you where it is.
The main valve typically looks like a wheel with spokes that you turn to the right, or a lever that you turn until it’s perpendicular with the pipe it’s connected to. You can always turn it off and then go try to run water somewhere. If the water does not run, you were successful in shutting off the main valve.
Should anything happen with any of your water-using appliances or areas of the home, you want to be able to stop the water so you can deal with the emergency. If you leave home for any length of time, like for summer vacation, the best insurance you can have against water mishaps and flooding while you’re gone is to turn the water off at the main valve before you leave.