The amount that you are billed for sewer usage is originally based on an average consumption of 12,400 gallons for a two-month period. Every spring, sewer usage is reassessed based on winter water usage that occurred during November, December, January and February. This allows for sewer charges to more accurately represent an average of what goes through our sewer system during the time of year that outdoor water usage, such as lawn watering, car washing and pool filling, are not as prevalent.