A Question Home Buyers Often Ask Is...
..."How can I tell if the main valve is on or off?"
Following are some answers:
Sometimes there is an arrow on top of the valve, when the arrow is pointing toward the house it is ON, when it is pointing toward the street it is OFF.
In some cases, if the top of the valve is in line with the pipe, it is ON, if it is perpendicular, it is OFF.
Other shut off valves are usually with supply lines under the fixtures they serve. These can be used to shut off the water if the water leak is down line from them or in the fixture.
Also, there is usually a shut off valve on the inlet pipe to the water heater. This can be used to shut off water to all hot water pipes in the house.