Winter Averaging for sewer charges set to begin soon

Water use during winter months should be monitored

MURPHY (September 26, 2022) Monthly charges for wastewater service, commonly called sewer service, are calculated using the average amount of water used within the household during November, January, and February of each year.

Known as the Winter Averaging process, consumption of water flowing through meters during these three months is used to calculate these charges for the following 12 months.

“Most cities use some sort of winter averaging to arrive at each home’s wastewater or sewer rates for the following year,” says Teresa Thompson, Manager of Customer Service. “Here in Murphy, the water measured through the meter during November, January and February gives us a good indication of what goes into our sewer system.”

This process is repeated the same way every winter. The amount of water used in each residence is recorded during these three months and the average becomes the monthly charge for sewer service over the following 12 months. December is considered a high-use month because of the holidays and is therefore not counted. This avoids adding a higher than normal month into the equation.

"There is still no accurate way to measure how much wastewater goes into the various drains, sinks, toilets, showers or baths in a home,” she said. “That makes it a challenge to determine how much to charge for wastewater service. The utility industry has developed this method of calculating the monthly charge in a manner that is as fair and equitable as possible.”

Averaging during the winter works best because utilities believe that most if not all the water used in a home is used indoors and thus discharged into the sewer lines. That’s because the majority of homeowners will curtail or eliminate outdoor irrigation during these months.

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 November, January, and February.

For example, water leaks, runny toilets, washing less than full loads in the clothes or dish washer, washing cars at home, or any other non-essential 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.

“During the winter months of November, January and February, residents should be mindful that their water usage has a direct effect on their sewer charges for the following year,” said Thompson.