Wastewater/WMA Calculations


How are wastewater rates calculated?

The wastewater fee on your monthly water bill pays for collecting and transporting wastewater (any water you flush, shower or rinse down the drain) and for taking care of the sewage system.

Residential wastewater rates are based upon a base fee depending on your meter size, plus a variable rate of $3.78 per 1,000 gallons of wastewater used. Your water meter measures your overall monthly water use, but there is no meter on your wastewater line. So how are wastewater rates calculated? The city uses the winter month average (WMA) of November, December, January, and February for wastewater calculations for residential customers since customers usually do not water their lawns during the winter and most of their water use is inside the house entering the sanitary sewer. Therefore, the city averages the individual household consumption during these months to set your residential wastewater rate for the year.

How is winter month average calculated? 

The city averages your water use in the months of November, December, January and February. The month with the highest consumption is dropped so that your winter month average is based on the three winter months with the lowest usage. 

(New residential customers who do not have a winter month average yet are billed at 80% of the current month until the WMA is established. The maximum they will be billed is 12,000 gallons.)

How to calculate wastewater fee and winter month average

What is my wastewater base fee?

The size of your water meter determines the monthly base fee for wastewater. Most residential meters are 5/8”, which means the base fee would be $12.37 per month. The size of your meter is typically printed on the face of your meter.

Wastewater Base (fixed charges per month)
5/8" METER $12.37
1" METER $13.40
1 1/4" METER $15.63
1 1/2" METER $16.29
2" METER $19.43
3" METER $28.77
4" METER $38.18
6" METER $59.25
8" METER $83.83
10" METER $107.32
12" METER $120.24

How do I lower the wastewater fee on my water bill?

Each year, residential customers set the maximum amount for billing of wastewater for the next 12 months based on their winter month average (WMA). Conserving water during the wastewater averaging period (November through February) will lower the volume of wastewater you will be billed for each month for the next year. Updates to the WMAs are updated every April. View the High Water Bill FAQ page for more tips on controlling your water bill.