Residential Sewer VOLUME Averaging

Once a year, the amount of water that a house uses is averaged to establish a set volume which is then multiplied by the current sewer rates. The calculation is added to the monthly service charge which results in the specific account’s monthly sewer charge. The City does not use a flat rate system. By using sewer averaging, the residents pay for what they create, they can influence their sewer charges, and the bill is more predictable. The averaging process considers the months of November, December, January, and February. Conserving water during this period will help control the monthly sewer volume charge.

Why is the volume of water consumed at the address used to calculate the sewer volume rate?

The inflow of water to the property is directly related to the outflow of sewer and the cost to process wastewater. By averaging the inflowing water consumption, a real expected outflow can be projected.    

Why does sewer averaging occur in the winter months? 

Historically, the four lowest water consumption months for residential customers are during the winter months.  Water use is lower during this time because most people are not engaging in outdoor watering.  Most winter water use is directly entering the sanitary sewer for wastewater processing.

The process of calculating sewer averaging: 

The water used during the consecutive months of November, December, January, and February is measured. The single winter month with the highest water usage is removed from the calculation. The water amount for each of the remaining three months is added together and then divided by 3. The outcome of this calculation reflects a conservative expectation of an address’s average incoming water volume.   

The rate to process the wastewater is billed per 1,000 gallons of volume.   This rate called sewer volume charge is multiplied by the specific house’s average winter water consumption (see above for the relation of inflow to outflow).  The outcome of this multiplication is then added to the base sewer rate. Each spring, the utility bill is updated to reflect a residence's new sewer volume that is effective for one year. It is expected that the sewer volume will be unique to each family's individual water inflow and outflow. 

        (Winter Water Volume Average   x   Sewer volume charge)  +  Monthly Service Charge  =  Residential Sewer Average

Do all customers have their sewer averaged?  

Only established residential customers are eligible for sewer averaging. New residents who move into an address will not be eligible until the next round of averaging because the process requires four full months of water use data. New residents will be charged the minimum base rate for sewer until they complete an averaging period in the property. 

How can I reduce my bill?   

You have control over the sewer average since you have control over how much water is used during the winter. Since residential sewer charges are based on each individual resident’s winter water consumption, you can lower your sewer charge by being water conscious during the winter months. Quickly take care of running toilets and dripping faucets. Keeping water usage as low as possible during the winter months will pay off for the next twelve months. 

Does Sewer Averaging lock in the sewer rate that I am billed for the next 12 months? 

The Sewer Averaging process locks in the quantity of sewer volume for which you are billed during the next 12 months but does not lock in the price you may pay.  The beginning of the City's fiscal year is October 1 and the price to process the volume of sewer may increase or decrease. Sewer rates that change in October will be multiplied by the averaged volume that was calculated in the prior winter. If the sewer rate increases or decreases, the amount billed for processing the averaged volume will change. While the volume is locked in for 12 months, the processing rate by which the volume is multiplied and the base rate may change.  

Please contact Utility Billing at 972-564-7304 with questions regarding sewer averaging, the sewer volume charge (SVC), or the sewer service fee (SSF).