The annual three-month period during which Melissa residents can have a positive or negative impact on their monthly sewer bill, begins in December.

The 90-day period is known as winter quarter averaging and lasts from December to February. Winter quarter averaging is a process used to calculate residential sewer charges by taking the average residential use of water during the months of December, January and February.

“Most municipal utility departments use winter averaging of some sort to determine each household’s monthly wastewater or sewer charges,” says Carrie Mikeska, Administrative Services Manager. “The rationale is that most of the water that enters the home, which we measure through the water meter, is likely going through the sewer system, since during the winter months outdoor watering is either severely limited or completely eliminated.”

The calculation process is repeated every winter. Simply stated, the amount of water used in each residence during the months of December, January and February is recorded, and the average for those three months becomes the monthly charges for sewer service over the following 12 months.

The amount of water discharged into drains is measured in thousand-gallon increments, and a cost set by the water supplier, is applied to the total.

“At this point, there is no reliable technology available that accurately measures how much wastewater goes into the various drains, sinks, toilets, showers or baths in a home,” she said. “That presents a challenge when trying to determine how much to charge residences for sewer service. To address that, we monitor the average amount homeowners use during the winter months, confident that most of it is going through the sewer.”

Averaging during the winter is preferable to any other time during the year because most of a household’s water is used indoors and thus discharged into the sewer lines. And, while many households may not see a big change from year to year, some homes may see a drop or rise in the wastewater charge because of what happens during the winter quarter averaging period.

Leaks, runny toilets, washing less than full loads in the clothes or dish washer, washing cars at home, or any other unnecessary water use in the winter will not only drive the monthly cost of water up, but can also show up in the sewer charges during the following 12 months.

“From December to February residents should be mindful that their water use has a direct effect on their sewer charges for the following year,” said Mikeska.