Irrigation System Leak

To check your irrigation system for leaks, start by turning off the irrigation main shutoff valve. This is usually 
located where the main service to the home splits to the landscape. After you have turned this off, return to 
your water meter to check the flow-indicator. If the flow indicator has stopped moving, your sprinkler system 
is the problem.
Turn the irrigation main shutoff valve back on and inspect each irrigation control valve that serves your sprinkler
system. Look for leaks or moisture; listen or feel for water flowing through the pipe which could indicate a bad
irrigation control valve. Many times moisture and continuous water flow found at the lowest sprinkler head are
sign of a bad irrigation control valve.

Repair kits and replacement parts are available at most home improvements stores.
Example of Irrigation Valve