I had a similar "issue" when I bought my house last year. Water service was never cut or transferred to the contractor's name who bought it and sat on it for a few years.
My first reading was the culmination of the previous 5 years. Our water dept is pretty slow (in thinking). They said I was on the hook for tens of thousands of gallons of water in the first 30 days I was in the house. A few calls to the supervisor's supervisor with repeated explanations cleared things up (and the previous owner/contractor was back billed).
Make sure you aren't leaking on the meter side of things. Here is New Orleans everything leaks. If you have a leak on your side of the meter you can run up a bill quick.--
"I have measured out my life with coffee spoons..." - T.S Eliot
"I have often regretted my speech, never my silence." - Publilius Syrus
Ma blog: »www.johndball.com