Water Useage Problem

The Schmidt's have been having a very high water bill and asked us to record the water meter readings when we did our weekly visits. Even though the sprinkler system and the water main was shut OFF we began recording the meter reading on each visit. On the first vist the meter read 175730. The next week the meter read 179800 which indicated 4070 gallons of useage. Thinking we may have read the meter wrong we waited until the next visit when the meter read 183950 indicating 4150 gallons of useage. At this point we decided to also turn the water off at the meter itself and when we returned the next day we found 0 useage. At this point the cause of the water useage has not been identified however fortunately water useage has stopped. Needless to say we have kept the Schmidt's informed of our findings and they have decided to have the problem taken care of when they return.