On September 27, 2022, Coppell City Council approved an amendment to the Water and Sewer Regulations ordinance that switched the current sewer billing method to winter averaging to bill for residential sewer service. Winter averaging is a method used to bill residential accounts for sewer service that uses winter months as the basis to calculate a customer’s sewer portion of the utility bill for an entire 12-month billing year.
The City started collecting data on November 1, 2022 to calculate each customer’s winter average. Residential customers will see these updates in their water bills beginning on April 1, 2023. New customers are assigned the city-wide volume average until their winter average is established. Winter averaging will not be used for commercial accounts.
Before moving to winter averaging, the City billed sewer service based on a fixed cost that capped billed usage at 13,000 gallons. Since sewer flow is not metered, this caused sewer service billing to spike during summer months when outside watering increased for activities, such as irrigation and pool use. Winter averaging helps remove from a customer’s bill the water used for outdoor activities. Outdoor water usage typically does not flow into the sewer system so removing it from total usage will provide a more reasonable estimate of the amount of water from household use that is flowing into the sewer system. Removing outside use from a customer’s sewer service calculation will result in customers’ bills only reflecting water used for household use, and not for irrigation.
To calculate a customer’s winter average, the City will track water usage for a five-month period, from November to March, of which the highest and lowest months of usage will be removed. The City will then calculate the average water usage of the remaining three months. This average monthly usage will be used to determine the monthly amount residential customers will be charged for sewer services. This established volume becomes the sewer volume that will be applied each month until a new volume is determined the following year.
The effect of winter averaging to residential water customers is expected to be negligible with an estimated 73% of bills that will see either no change or a decrease in their sewer charges. For more information about winter averaging, visit coppelltx.gov/winteraverage.