There are quite a few basic plumbing jobs that require you to turn off your home's water supply. Whether it is a job that involves plumbing repair, a bathroom addition or installing an automatic sprinkler system, it's a good idea to know how to turn on and turn off your water meter.
Remove the cover for the water meter. These covers are usually made of heavy cast iron, and you may need to insert a wrench in the key hole, turn it slightly and lift the cover off.
Grasp the "T" handle of the water meter key and lower the other end down toward the water meter.
Place the notched end of the key over the raised piece of metal atop the valve. When the water supply is off, this piece of metal will be perpendicular to the direction of the pipe. It will often be shaped like an arrow, or have an arrow next to it.
Turn the valve 1/4 of a turn counterclockwise to turn on the water supply. On most meters, the arrow will now be in line with the pipe.
Replace the cover.