Water bill math equation

We pay $150 for 3 months and have 1 acre foot of water allotted to us which translates to 325830 gallons of water for the year.

The third quarter came to an end, I got our bill, and to that point in the year we had used 323980 gallons.

325830 - 323980 = 1850 left for the year

Um, that wasn't going to go very far.

Or so I thought.

I got our new bill for the fourth quarter and was very nervous to open it. Tyler and I took bets on what it would be. He thought $300 extra ($450 total, ouch!); I was hoping it was not more than double ($300).

I peeked inside and saw this:
That couldn't be. So I glanced at this little box:
And then it hit me. The water year/bill goes from October to October. We had actually come in under our allotment, even with all the grass, trees, shrubs, stream, splash pad we had put in.
This is one bill I will happily pay.