Massive water bill and water meter reading--despite no leak

[Pauline Vu]

We recently turned on the water for a new property so that we could begin renovating it (3 small houses on a single large lot). The water had been shut off to this property for at least 2 years, probably more like 3-4 years. We got it turned on in mid-February for basic usage (toilet, faucet) while we fix up the units, and were stunned when we got a huge bill; the private water company claimed we'd used almost 116,000 gallons of water in 12 days. We complained, but they said we must have had a leak. 

We checked the pipes, but couldn't find a leak. We hoped the bill was a fluke, given that there was no leak, but for the next month the meter read that we'd used almost 407,000 gallons over 28 days! (so almost 523,000 gallons over 40 days)

The following month usage fell on its own to 37,400 gallons over 30 days. I should mention, during all this time we didn't have any tenants there yet (we didn't even have water heaters installed yet). We just had one toilet working and used two faucets. Our personal usage didn't change dramatically from when we started renovating the units.

I'm trying to determine what explanation there could be for this. We don't believe there was a leak because 1) our own investigation--including digging to the pipeline--never found anything; and 2) the pipes are only one feet underground, so if 523K gallons of water was coming out somewhere, we think we would've seen a pool of water or some wetness somewhere on the property (there was never any wetness).

My research has determined that it's possible the pipes had air in them and that the meter was reading that. We did notice that when we used the faucets, air would always come out first before water. But is it possible air could account for that high of a reading? And if not, what else could explain it, and also the fact the "water usage" has dropped so much from our first to latest bill? Also, any advice for what to say to the water company? They've been adamant that the meter is right and that we must've initially had a leak (although they finally sent someone to read the meter recently and are now saying there is no leak and that we must've repaired it, which we didn't do since we never found one to begin with).