Winter Averaging

Coppell City Council approved amending the Water and Sewer Ordinance. The amendment was switching the billing method to winter averaging. The method will go 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 in the following year. It 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 will be removed, and then the City will calculate the average water usage for the remaining three months. The calculated average will be used as the monthly sewer volume beginning each April for the following 12 months. A new volume is calculated each year. The City will begin collecting usage data every November starting in 2022. New customers are assigned the city-wide winter average until their individual winter average is established.   

Why is the City moving to winter averaging?

The transition to winter averaging is 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 ensures customers are not charged for water that does not flow into the sewer system.

Will this cause my water bill to increase? 

The effect of winter averaging to residential water customers is expected to be negligible. It is estimated that 73% of bills will 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.