How is the sewer portion of a single-family residential bill calculated?
Since water is mostly used indoors during the cooler months, and likely ends up processed at a River Authority treatment plant through the sewer system, this amount serves as the basis for winter averaging. The winter averaging period is December, January, and February.
Customers who do not have a winter record of water usage will be billed a system average.
Customers who have established a “Wintertime Monthly Average,” (the calculated average of water usage for a single-family residential account during three consecutive billing periods, starting with the first billing period after November 14 of each year) the sewer rates are determined by using three consecutive consumption usage during the winter averaging period.
The consumption history of gallons of water used during the months of the winter averaging period is applied to determine an average amount used. The average amount used is multiplied by the variable rate. The variable rate is determined by the cost to treat and dispose of wastewater, which includes operations and maintenance activities. The variable rate is applied to every 100 gallons.
The minimum fixed rate is the debt repayment on monies borrowed for a major capital improvement, such as expanding the wastewater treatment plant. This rate is in effect beginning July 1st and stays in effect until the following July where the new winter averaging is applied.
The regulatory assessment fees are for The Texas Commission on Environmental Quality as mandated by Senate Bill No. 2, passed by the Texas Legislature in Special Session effective September 1, 1991.
Average x Variable Rate / 100 gallons + Fixed Rate + Regulatory Fees