If the water meter is still spinning when all taps are off in your home then you probably have a water leak. If your home has a shut off valve, turn off the water supply to your home. If the water meter stops spinning, the leak is in the home side of the supply. If the meter keeps spinning then the leak is obviously from the toby to your shut off valve, most likely from the meter itself or from piping in the ground.

Plumbing leaks in supply line