16,000 gallons!!!

Got a note from the St. Pete utility department saying that we used 16,000 gallons of water last month and thought we should figure out why. Well...its a mystery that must be explained either by 1) a defective meter 2)a misread by the meter reader or 3) someone is stealing our water. to put this in perspective our pool only holds about 10,000 gallons of water. And in a normal month of no one living at the house we use about 3200 gallons of water (primarily from water evaporation from the pool and the odd toilet flush here and there when we visit the house to check it out) . So here is the mystery...1) no one is living in the house 2) all but one toilet is shut off and we checked the other one it is NOT running 3) our irrigation is from an onsite well (and we only are allowed to water once a week anyway) 4) we had the pool and equipment checked today...no major leaks...only one tiny one we've had for months that can't use more than a couple of gallons a day 5) there are no marshy areas around the house 6) there is no water under the house 7) there is no "surprise" water in our neighbors yards. so you tell me...misread, defective meter, or someone drove a water truck up to our house in the middle of the night and stole 2 trucks worth of water. hmmmm.