I have a water leak from an outside pipe. I shut off water going into the house, leaving only the outside plumbing on, and the water meter indicator spins, indicating water being used somewhere.

Is there any way to tell where the leak is coming from short of digging up my water pipes? I only have two outside faucets (yes they are turned off, no they don't leak), but the pipes leading to them go all the way around the house, probably over a hundred feet of pipe. Somewhere along this hundred foot section of pipe there is a leak. I can dig the entire mess up if I have to, starting at the water meter, but is there an easier way to find the leak?

I live in the southern Wilamette Valley, Oregon. It rains. Every day. Day in and day out. The ground is mud from October to June, so looking for a wet spot or green spot is not really an option.