Why is the water back?

Some of you may remember how, back in February, I expressed my frustration that our household's water usage had been gradually creeping upward over the years for reasons that I couldn't understand. Where once our quarterly water bill had consistently fallen into the first tier of usage (under 800 cubic feet), it had started falling more and more often into the second tier (800 to 999 cubic feet). And naturally, we did nothing to reduce it by adding three new trees to the yard in March, each of which needs a minimum of 5 gallons of water each week—not to mention the five cherry bushes and the dozen raspberry canes. So it came as no surprise when our next water bill, covering the period from February through mid-May, was all the way up to 910 cubic feet. Disappointing, yes, but hardly shocking.

What really baffles me is the bill I got yesterday, which covers the period from mid-May through early August. This includes the hottest part of the summer, during which we increased our tree-watering schedule to three times a week, and also continued to water the bushes and the vegetable garden on a regular basis. And our water usage for this period was...400 cubic feet. Half the cutoff for the lowest tier. Our daily water use, which had been over 70 gallons in the spring, had somehow dropped to less than 36 gallons in the summer. That's less than it's ever been, in all the time we've owned this house.

Naturally, this is good news—or rather, it would be if I could allow myself to believe it. But frankly, I just can't grasp it. How is it possible that, with no significant change in behavior, our water usage climbed from around 50 gallons a day to 70—and then, out of nowhere, dropped to below 40 again? Especially when the one change in behavior we had made at that point was the after addition of a bunch of thirsty plants to our landscape, which should have increased our water use rather than decreasing it?

I'm beginning to wonder whether our water meter is actually hooked up to anything. Maybe the borough just has a guy coming round to our house and setting it forward by a random amount each month. In fact, maybe he saw my post back in February about how high our water bill was getting and decided to drop it dramatically this month, just to freak me out.