If you suspect that water may be leaking from a broken pipe or fitting somewhere underground, the following simple test will let you know for sure:
1 Turn off every faucet, fixture, and appliance that uses water—even the ice maker. Do NOT turn off the main shutoff valve.
2 Open the water meter’s cover so that you can see the gauge.
3 Mark the rim of the gauge where the needle is pointing (if there are several dials, mark the one that indicates 1-cubic-foot increments).
4 Leave the water shut off for 30 minutes, and then see if the needle has moved from the mark. If it has, your plumbing is leaking somewhere.
5 You can look for signs of a leak, such as sinkholes or mushy areas of ground, but you may have to have a professional find it.