I have a small leak from the meter to the house and I can not find it under ground. We have tried a probe stick , but the whole yard is soft. We tried looking for green grass area, but I have green patches over the whole yard. Please help me; how can I find this small but expense leak with digging up the whole yard ?

Why do you think you have a leak if you can not find it? Usually if you have a leak in the water line you will see soggy ground and/or greener grass etc...
Is it possibly you have a leak in a valve or toilet float valve etc??