Sewer Surcharge Calculation

Typical Commercial Customer

How is the sewer surcharge calculated?

The sewer surcharge is charged to owners or occupants of land in the City of Windsor who have access to a sewage system and is calculated as follows:

1. The wastewater fixed charge is based on the size of the meter (see table above);
2. For the period from November 1 through to April 30 (known as the winter consumption), the actual consumption of water is charged at a rate per cubic metre of water.
3. For the period from May 1 through to October 31 (known as the summer consumption), the actual summer consumption of water is also charged at a rate per cubic metre but is reduced by any excess summer usage above the winter average usage consumption of water. (Note: Therefore, charges do not include increased summer consumption costs related to watering the garden, filling pools, washing cars, etc. during this period).

Examples:

Residential Customer Using 18 cubic metres (m3) of water/month in the summer and with a winter average of 12 m3 of water/month

The fixed charge portion of the sewer surcharge will be $21.65 for residential customers.

The consumption charge portion of the sewer surcharge is calculated as follows:

• Actual water usage (18 m3 of water at $3.37/m3) $60.66
• Reduction for excess summer usage (6 m3 at $3.37/m3) $20.22
• Total Waste Water Consumption Charge $40.44
• Total Waste Water Charges (Fixed + Consumption) $62.09

Commercial Customers Using 1,000 m3 of water/month in the summer and with a winter average of 900 m3/month

The fixed charge portion of the sewer surcharge will be $194.85 for a customer with a 1-inch service.

The consumption charge portion of the sewer surcharge is calculated as follows:

• Actual water usage (1,000 m3 of water at $3.15/m3) $3,150.00
• Reduction for excess summer usage (100 at $3.15/m3) $315.00
• Total Waste Water Consumption Charge $2,835.00
• Total Waste Water Charges (Fixed + Consumption) $3,029.85

Why does the sewer surcharge also include fixed charges and not just water usage?

Fixed charges to connect to the water system are also factored into the calculation of the sewer surcharge, as they are an integral part of the entire water distribution process. There are both costs that fluctuate with the amount of water that is discharged into the sewer system and costs that are fixed in nature that need to be funded no matter what the usage levels are. However, approximate 70% of the sewer surcharge amount is based on the amount of water actually used.

Allocation of Fixed and Variable Costs

The way the sewer surcharge is calculated was changed in 2009 to better reflect the amount of water the consumer actually uses. In order to be more closely aligned with the provincial average as it relates to the fixed/consumption fee ratio for sewer charges, the formula is based on approximately 30 percent fixed cost and 70 percent consumption cost for average residential water users. Consumers are able to better manage their sewer surcharge costs by reducing their water consumption. Lower water consumption will reduce the strain on the sewer infrastructure, which could delay the need for future capital expenditures, thus saving money over the long term.

Allocation Between Residential and Commercial Customers

Consideration was again given in this year’s review to the proportion of costs assigned to residential and commercial customers. Historically, water consumption has typically been split 47% and 53% respectively between residential and commercial customers based on actual usage. The City’s model, however, historically allocated these costs at a 68% to 32% split. This allocation had been in place for several years and was essentially left status quo over the past number of years as a means to assist the business community during the economic downturn experienced a decade ago. Given the recent changing economic conditions in the city and the fact that Windsor’s commercial and industrial wastewater charges fall below our peers, effective in 2019 allocation of these costs began to move to be more reflective of actual consumption patterns. The 2024 sewer surcharge model has been developed with a cost split of 55% residential and 45% commercial, which is keeping in line with the cost split in the prior year. This split will continue to be assessed annually, as usage patterns stabilize from the COVID-19 pandemic impacts, with the goal of a continued shifting in future years until the model is aligned with the actual consumption-based allocation.

How will sewer surcharge rates affect me?

• As a result of the increase for 2024, the sewer surcharge rates for the combined fixed and consumption portions of the wastewater bill will result in a $5.82 monthly/$69.84 annual increase in costs for the average residential customer. This is assuming that the homeowner's annual water consumption of 200 m3 remains unchanged in comparison to 2023.
• The trend in Windsor, as well as across the province, has shown a decline in water usage. Consumers can reduce costs through continued conservation. Therefore, the average resident may see a lower than average increase in their wastewater charge.