Marie, The class action suit you speak of would have no bearing on the water main coming into your home; that suit is primarily because of connection failures, and this won't be what you have coming into your house underground.
What you need to do is locate the leak, and there's another step to finding it; you must turn off the main shutoff valve where the water main enters your home, THEN check the meter after a time. If the reading has changed, then you have a leak in the main before it enters the house. (Also, many meters have a small red or blue triangle under the glass near the readout, which you can visibly see spinning with very little water passing by, so if you can watch this you needn't wait 2 hours to decide there's a leak)
If there's no change in the reading with the main valve closed, then open the main valve and start checking for things like leaking toilet flappers. A slowly leaking toilet can use a surprising amount of water!