Wastewater and Stormwater Fee Calculation
Stand-Alone Wastewater Fee Rates
The Wastewater Fee is calculated using Stand-Alone Uniform Sewer Rates. This is made up of the Wastewater Fixed Charge that is based on the size of the meter connected to your address and a Wastewater Consumption Charge based on water usage. In order to exclude increased summer water usage that is estimated not to be returned to the sewer system, the water usage for the wastewater consumption charge will be calculated as the lower of actual water usage or the winter average usage.
The Fixed Wastewater Fee rates by meter size are listed below:
Fixed Wastewater Fee Rates
Residential Accounts
Stand-Alone Fixed Wastewater Charge: $12.89
Non-Residential Accounts
| Meter Size | Stand-Alone Fixed Wastewater Charge |
|---|---|
| Less than 1 inch/25 millimetres (mm) | $12.89 |
| 1 inch/25mm | $116.57 |
| 1 1/2 inch/40mm | $273.07 |
| 2 inch/51mm | $455.84 |
| 3 inch/75mm | $819.25 |
| 4 inch/100mm | $1,450.72 |
| 6 inch/150mm | $2,648.92 |
| 8 inch/200mm | $4,413.61 |
| 10 inch/250mm | $7,270.84 |
| 12 inch/300mm | $10,470.00 |
2025 approved rates for both residential and non-residential customers are outlined in the table below:
Typical Residential Customer
2025 Residential Wastewater Charges
| Charge | Rate |
|---|---|
| Variable Consumption Charge | $2.01 per cubic metre |
| Fixed Charge | $12.89 |
2026 Residential Wastewater Charges
| Variable Consumption Charge | Rate |
|---|---|
| 0 cubic metres | No charge |
| 1 to 5 cubic metres | $1.75 |
| 6 to 17 cubic metres | $3.40 |
| 18 to 30 cubic metres | $3.55 |
| More than 30 cubic metres | $3.58 |
| Fixed charge | $12.89 |
Typical Non-Residential Customer
Non-Residential Accounts
| Wastewater Rates | 2026 Rates (no change from 2025) |
|---|---|
| Wastewater Fixed Charge | $116.57 for typical 1-inch service. See link below for further information |
| Wastewater Consumption Charge | $1.66 per cubic metre of water used (reduced for excess summer consumption) |
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:
- The wastewater fixed charge is based on the size of the meter (see table above);
- For the period from November 1 through to April 30 (known as winter consumption), the actual consumption of water is charged at a rate per cubic metre of water.
- For the period from May 1 through to October 31 (known as 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 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 during the winter period (November 1 to April 30) is calculated as follows:
Usage Step 1 (5 m3 at $1.75) = $8.75
Usage Step 2 (12 m3 at $3.40) = $40.80
Usage Step 3 (1 m3 at $3.55) = $3.55
Total Actual water usage (18 m3) = $53.10
The consumption charge portion of the wastewater fee during the summer period (May 1 to October 31) is calculated as follows:
Usage Step 1 (5 m3 at $1.75) = $8.75
Usage Step 2 (7 m3 at $3.40) = $23.80
Total Winter average water usage (12 m3) = $32.55
Total wastewater charges during winter period (fixed + consumption) = $65.99
Total wastewater charges during summer period (fixed + consumption) = $45.44
Non-Residential Example:
Commercial customer using 1,000 m3 of water/month in the summer with a winter average of 900 m3 of water/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 during winter period (November 1 – April 30) is calculated as follows:
- Actual water usage (1,000 m3 of water at $1.66/m3) = $1,660.00
- The consumption charge portion of the wastewater fee during summer period (May 1 – October 31) is calculated as follows:
- Actual water usage (900 m3 of water at $1.66/m3) = $1,494.00
Total wastewater charges during winter period (fixed + consumption) = $1,776.57
Total wastewater charges during summer period (fixed + 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, approximately 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
| Residential Tier | Impervious Area | 2026 Residential Monthly Rate |
|---|---|---|
| Tier 1 | 27 to 200 m2 | $8.00 |
| Tier 2 | 201 to 325 m2 | $10.00 |
| Tier 3 | More than 326 m2 | $12.00 |
Non-Residential and Multi-Residential
Fee based on amount of impervious area
| Non-Residential and Multi-Residential | Flat Rate
|
|---|---|
| Per square metre | $1.26 per m2 |
Follow this link for more information on Wastewater: Stormwater Financing (Let's Talk Windsor)