Businesses in Toronto may be eligible for a rebate on water not discharged into the sanitary sewer system (i.e. water evaporated from cooling towers or used to make a product). The rebate is based on the percentage of water not returned to the sanitary sewer system, and is applied to the sewer portion of the water rate.

Eligibility Criteria

The Program is open to industrial, commercial and institutional water customers that meet the following qualifications:

Property’s Total Annual Water Consumption Sanitary Contribution Amount
≤1500 m3 ≤ 80%
>1500 m3 but ≤15,000 m3 ≤ 85%
>15,000 m3 but ≤ 1,500,000 m3 ≤ 90%
>1,500,000 m3 ≤ 95%

Water used outdoors (i.e. for irrigation) is not eligible for the Sewer Surcharge Rebate Program. For full eligibility criteria, read By-law No. 849 – Water and Sewage Services and Utility Bill.

Step 1: Let us know you are interested

Submit a letter of intent by email to that includes:

  • Company name
  • Facility address
  • Contact information (full name, phone number, email address)
  • Utility account number
  • Water meter serial number(s)

Step 2: Submit documentation

You will have nine months from the date your letter of intent is received by the City to submit all required documentation (see Application Requirements section below). For City staff to evaluate the application:

  1. All submissions must be stamped and certified by a Professional Engineers of Ontario licensed engineer, including revisions to the Sanitary Sewer Flow Differential Summary form.
  2. The application must contain all required supporting material.

Step 3: Assessment and rebate

If all documentation and information is received within the nine-month period, and your application is eligible, the rebate will be retroactive to the date your letter of intent was received. If the application received is incomplete, and all additional information is not received within 10 business days of being requested by the City, the rebate will be retroactive to the date all information is received.

The first submission is valid up to February 1 of the following calendar year.

Step 4: Subsequent rebates

To continue to receive the rebate after the first year, all documentation (except the letter of intent) must be submitted annually by February 1.

If a renewal application is not received by February 1, or additional information requested by the City is not received within 10 business days of the request, the date of the rebate will be retroactive to the date all requested information is received.

Once the City receives your letter of intent, you have nine months to submit the following:

  1. Copies of water bills for the last 12 months for systems, sites and/or processes responsible for directing water away from the sanitary system. Figures on these bills should be referenced in any summaries, calculations or formula that make up the submission.
  2.  A detailed engineering report that:
    • identifies the total amount of water purchased from the City for the past 12 months (this amount should match the total of the water bills submitted)
    • describes the processes and/or products that use water.
    • provides copies of any maintenance records or water quality or testing logs (if applicable)
    • includes electronic production records (if applicable)

Please use the City’s templates for all cooling towers and boilers.

While the report may be prepared in any format, it must have enough detail to allow City staff to analyze each water source and effluent discharge process. This includes:

  • All calculations that clearly reference industry accepted equations and formula.
  • Equations that reference the water bills submitted for the past 12 month period.
  • Equations that reference production records for water captured by products (if applicable).
  • Weekly or monthly water meter readings, depending on what the calculations represent.
  1. A completed Sanitary Sewer Flow Differential Summary

Should you require assistance locating an engineer or consultant to help prepare the paper, you may contact Partners in Project Green.

Annual application process

To continue to receive the rebate, all documentation (except the letter of intent) must be submitted by February 1 of each calendar year.

Please submit the following meter reading forms:

  • Single Cooling Towers
  • Multiple Cooling Towers
  • Single Boilers
  • Multiple Boilers

Cooling towers

Makeup (feedwater) and blowdown water must be submetered.


Makeup (feedwater) must be submetered, while blowdown water must be measured and/or controlled in a consistent and predictable manner. Boiler blowdown measurement/control and any corresponding calculations must be described in sufficient detail and the Boiler Meter Readings form completed accordingly. This information is used to determine the water that is evaporated instead of being returned to the sewer.

In 2020, a business consuming 100,000 m3 and diverting 20% of purchased water could receive a rebate of $46,438 (100,000 m3 x $4.0735/m3* x 57%** x 20%).

Annual Water Bill for General Customer: 
$407,350 (100,000 m3 x $4.0735)

Annual Water Bill with Sewer Surcharge Rebate: 
$360,912 ($407,350 – $46,438)

*Rebate calculation applies to water rate paid by consumer, either the general (Block 1) or industrial (Block 2) water rate. See the current water rates.

**57% represents the portion of water rate charged for sewer use discharge (sewer surcharge). This rate of rebate is determined by City Council and can be subject to change.