First it is important to understand how to read your water meter.
To check for leaks follow these steps:
Turn off all water taps inside and outside your home. Record the meter reading and return in two to three hours to check for movement. If the meter reading has changed, you may have a leak.
Many meters have a small red (or blue) triangle on the meter face, designed to detect even small leaks. If this red triangle is moving when you have all water off inside and outside your home, you may have a leak.
Common sources of leaks are a toilet that is running, a constant drip in a sink or outdoor faucet, a loose or dripping washer connection, a home water treatment unit, an evaporative cooler unit, or a sprinkler system.
Shutting off Water at Your Meter
Should you need to shut off the supply of water to your house (to repair a leak, etc.) there is usually a shutoff valve right at the water meter. The water meter shutoff valve typically looks like a brass bolt located on the pipe connected to the water meter. Often this bolt will have an arrow stamped into the top indicating the direction of flow. To shut off the water supply, use a large pair of pliers to turn the bolt 90 degrees. You can check to make sure that the water is off by operating a faucet or hose bib. To restore the water supply to your home, simply turn the bolt back to the position you found it.