Sewer Surcharge Calculation

Typical Commercial Customer

How is the wastewater fee calculated?

The wastewater fee 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 wastewater fee will be $12.89 for residential customers.

The consumption charge portion of the wastewater fee is calculated as follows:

• Actual water usage (18 m3 of water at $2.01/m3) $36.18
• Reduction for excess summer usage (6 m3 at $2.01/m3) $12.06
• Total Wastewater Consumption Charge $24.12
• Total Wastewater Charges (Fixed plus Consumption) $37.01

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 wastewater fee will be $116.57 for a customer with a 1-inch service.

The consumption charge portion of the wastewater fee is calculated as follows:

• Actual water usage (1,000 m3 of water at $1.66/m3) $1,660.00
• Reduction for excess summer usage (100 at $1.66/m3) $166.00
• Total Wastewater Consumption Charge $1,494.00
• Total Wastewater Charges (Fixed plus Consumption) $1,610.57

Why does the wastewater fee 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 wastewater fee, 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 wastewater amount is based on the amount of water actually used.

Allocation of Fixed and Variable Costs

The way the wastewater fee 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 wastewater 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 2025 wastewater fee 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.

Stormwater Fee Rates

Your stormwater fee will be based on the impervious area on your property.

Residential Accounts

Tiered flat rate based on impervious area

Non-Residential and Multi-Residential

Fee based on amount of impervious area

Follow this link for more information on Stormwater: Stormwater Financing (Let's Talk Windsor)

How will the wastewater fee and stormwater fee rates affect me?

• In order to obtain an accurate comparison of the increases for 2025, both wastewater and stormwater rates will need to be considered together. It is important to note that most residential customers will see a decrease to their overall waster and stormwater costs. The estimated fee impact on non-residential (for example, commercial, industrial, institutional) and multi-residential property owners will vary depending on property type, water usage, and amount of impervious area. It is expected that many small and medium-sized businesses will see a reduction to their combined stormwater and wastewater fees in 2025. However, those having large impervious areas, such as very large facilities and/or parking lots, can expect to see an increase. Properties that currently do not have a water service and use no water will have a new fee as a result of this new method of calculating the stormwater fee. This aligns with the principle of everyone paying their fair share of the costs under the new model.

Impact on the Average Residential Customer (Tier 2 using 200 m3 of water)

• The wastewater fee rates for the combined fixed and consumption portions of the wastewater bill will result in a $31.50 monthly/$378.00 annual decrease 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 2024.
• The stormwater fee rate for the average resident in Tier 2 will result in a $28.17 monthly/$338.04 annual increase in costs.
• Overall, the average resident will see a decrease of $3.33 monthly/$39.96 annually on their water bills related to wastewater and stormwater.

Average Monthly Residential Total Sewer Cost – Tier 2

Note: Assumed average monthly consumption of 16.67 m3 or of 200 m3 annually

Note A: Prior to 2025, the Stormwater rate was included as part of the Wastewater Sewer Surcharge Rates.

• 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.