Our town has a minimum monthly water charge of $15. If you use an amount below a certain threshold, you are billed this minimum amount. Beyond that, it starts to go up per gallon of usage.
For the month of January 2008, we used only 720 gallons and were charged the minimum! That hasn't happened to us since before we started gardening and raising poultry.
We might be getting some rain, fellow southerners, but the drought isn't over. Let's all keep conserving as much as possible...