Stormwater Credit for Businesses


Municipal Office

395 Mulock Drive P.O. Box 328 Station Main, Newmarket, Ontario
L3Y 4X7

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Purpose of Credit program 

The purpose of the Stormwater Credit Program is to encourage the use of stormwater management controls through the use of low impact development (LID). LID's include permeable paving, soak-away pits, infiltration trenches, rain gardens and rainwater harvesting.


Commercial and Industrial properties that are classified in the high runoff level group can apply for a stormwater credit towards their stormwater charge.

Property owners must demonstrate that all, or portions of their property drains to an eligible 'best management practice' (BMP)​ that meets specific evaluation criteria outlined below: ​

​Credit Category​Evaluation Criteria​Credit Applied
​Low class rate​

1. Reduce existing Peak Flow Rate by a minimum of 60% up to and including the 1:100 year storm and;

2. Capture and infiltrate the first 20mm of each storm event.

​Low class rate applied to area treated ​that meets the evaluation criteria
​Medium class rate1. Reduce existing Peak Flow Rate by 30% for up to and including the 1:100 year storm and;

Capture and infiltrate the first 10mm of each storm event.​
​Medium class rate applied to area treated that meets the evaluation criteria 
​Pollution prevention ​Documentation which outlines onsite SWMF’s and/or BMP’s prevents pollutants from leaving the site.​5% reduction
Significant green space ​​Green space area is more than 25% of the sites total parcel size.​Low class rate applied to green space area 

Please note that green space, grassed or landscaped areas on the property will not qualify for a credit unless:

  1. These areas are treating stormwater from non-green space areas and meet the evaluation criteria for one of the credit categories or;
  2. The green space area is more than 25% of the sites total parcel size and the space either contains trees, which contribute to the Town’s urban canopy or other significant natural heritage features.  If the landowner has green space, which contains mostly sod, but agrees to plant trees in that area in order to contribute to the Town’s urban canopy, this would also qualify for the green space credit. 

Stormwater charge calculation with credit program​

Depending on the evaluation criteria met, the portion of your property that has BMP’s will be charged either a low or medium class rate. Your stormwater credit will be calculated by combining the lower class rate for the area treated with a BMP along with the high runoff rate to the area that doesn’t have BMPs. 

Types of Credit

There are three types of credits for the stormwater charge that applicants can apply for: New credit, credit update or credit renewal. ​

  • New Credit
    • A stormwater management credit for a newly installed BMP or existing BMP for which a credit does not currently exist. 
  • Credit Update
    • A stormwater management credit for an existing BMP where changes have been made or where additional BMP’s have been added since the previously approved credit. 
    • If Credit approved BMP's are added, expanded, reduced or removed or in any way modified such that their level of performance relative to their approved credit amount has changed, credit holders must follow the Credit Update Application Process​. A Credit application must be submitted no later than three (3) months after any Material Change to the approved credit application.
  • Credit Renewal 
    • ​A stormwater management credit to renew the existing approved credit as part of the five-year renewal requirement. A bonus credit is available if applicants can demonstrate existing Stormwater Management Facilities (SWMF) that is being properly maintained.  
    • The renewal application is focused on demonstrating that the installed BMP's are properly maintained and in a state of good repair. In order to receive the Credit on an ongoing basis, approved applicants must follow the Credit Renewal Application Process and BMP's will be subject to inspection by Town staff to ensure compliance.​

For more information on how to apply for a stormwater credit for commercial and industrial properties, visit our application process page​

Please review the Stormwater Management Fees and Charges By-law 2016-67 for additional information and requirements.