Water meter has very wet mud around it but the dirt outside of the meter's tube is dry.. Where is my leak?

I got a water bill for $96. Apparently we consumed 4x the amount of water we have ever used in less than a month. I turned off the building-shut off valve inside, the indicator at the meter was still churning. I had the utility company shut off ALL water coming through, indicator has stopped--which means the leak is between the meter and the house. Now it is up to us to dig up my whole yard to find the leak. However, only the dirt immediately surrounding the meter is very muddy and wet, but anything outside the cylinder which encases the meter itself is dry dirt. What does that mean for me?