Winter Averaging

The Coppell City Council approved an amendment to the Water and Sewer Ordinance that switched the sewer service billing method to winter averaging. This method went into effect April 1, 2023.  

What is winter averaging?  

Winter averaging is a method used to bill residential accounts for sewer services. Winter averaging uses water usage during winter months (November - March) as the basis to calculate the sewer portion of a customer’s utility bill for an entire 12-month billing year. The established volume becomes the sewer portion of a customer's utility bill that will be applied each month until a new volume is determined the following year. Winter averaging is not used for commercial accounts. 

How is the winter average calculated?  

The City tracks water usage for a five-month period, from November to March. The highest and lowest months of usage are removed, and then the City calculates the average water usage for the remaining three months. The calculated average is then used as the monthly sewer volume beginning each April for the following 12-month period. A new volume is calculated each year. Beginning in 2022, the City begins collecting usage data every November. New customers are assigned the city-wide winter average until their individual winter average is established.  

Why did the City move to winter averaging?

The transition to winter averaging was intended to more accurately measure a customer’s wastewater use flowing into the sewer system. Before moving to winter averaging, the City billed wastewater based on a fixed cost that capped billed usage at 13,000 gallons. Since sewer flow is not metered, this caused sewer billing to spike during summer months, when outside watering increases for activities, such as irrigation and pool use. Monitoring water use during the winter months provides a more accurate picture of indoor water use and, therefore, wastewater use. This helps ensure customers are not charged for water that does not flow into the sewer system.

Did this cause my water bill to increase?

The effect of the transition to winter averaging to residential water customers was negligible. It was estimated that 73% of bills would see either no change or a decrease in their sewer charges. Winter averaging also encourages water conservation and allows customers to have more control over their wastewater bill. Customers who maintain low usage during the winter months will enjoy a lower sewer rate for the following year. Water usage can be monitored in the MyH2O Customer Portal.

If you have additional questions about winter averaging or your bill, please contact Utility Billing at 972-304-3695. 

Winter averaging video