The sewer district conducts an annual water usage update. The water usage or volume charge portion of your bill will be adjusted each year to reflect your current average water usage. Each spring your water supplier provides us with your actual water usage for November, December, January, February and March. We use the winter months so we are not charging you for outdoor usage like watering your lawn or washing your car. These five months are averaged, and this figure is applied to the volume charge portion of your billing from May of one year until April of the next.