Look at the provided diagram. If the cut off valve is running with the pipe, it is open (water is on), if the cut off valve crosses the pipe, it is closed (water is off). Another way to tell is the “ears” on the valve the water department uses to lock your water meter in the off position. If the “ears” line up so that a lock can go through them, it is closed. You can use a pair of pliers, channel locks, vice grips, etc. or you can purchase a meter key from most hardware stores.