feed-image Feed Entries
Decrease font size Default font size Increase font size

Backflow Prevention Program

Purpose of the Program

To fulfill the Town of Grimsby's continued commitment to provide a safe, clean supply of drinking water to its customers and to uphold all applicable legislative and regulatory requirements, the town has developed a backflow prevention program in combination with a new municipal By-law. The purpose of this program is to protect residents of the Town of Grimsby and other users of the Grimsby Water Distribution System (WDS) from harmful contaminants that may enter the water system through cross-connections or backflow. By-law 09-73 known as the "Backflow Prevention By-law" was approved by Town of Grimsby Council Septembter 21st, 2009.


Application of the Program

The Backflow Protection Program will help to ensure that the potable drinking water system is protected  against the entry of any contaminants. This is accomplished through the installation of backflow prevention devices at potential sources of contaminants.

Backflow occurs as a result of back siphoning, back pressure or both. Back siphoning is a reversal of the normal flow of water caused by a negative pressure in the water line. Back siphoning occurs when there is a reduction or stoppage of main water supply pressure, typically due to nearby firefighting activities or watermain breaks/repairs. Backflow can also occur when there is an increase in the downstream water pressure (i.e. in a private building/structure, etc.) above that of the supplied water pressure (i.e. in the municipal watermain), referred to as back pressure. Backpressure can also occur when there is a direct cross-connection between the potable drinking water supply and another process line which has the potential to transmit a contaiminant into the potable drinking water supply.

The Backflow Prevention Program and By-law are applicable to industrial, commercial, institutional and multi-unit residential (greater than 3 stories and/or total gross floor area exceeding 600m2) buildings/ structures.



  • "Backflow" means the flowing back or reversal of the normal direction of flow of water.
  • "Backflow Prevention Devices" means a device that prevents backflow which is certified to the CSA standard.
  • "Cross-connection" means any actual or potential connection between a potable water supply or system and any source of pollution or contamination and includes any by-pass, jumper connection, removable section of pipe, swivel or changeover device and any other temporary of permanent connecting arrangement through which backflow may occur.


Frequently Asked Questions

Click here for a list of frequently asked question relating to the Backflow Prevention Program/By-Law.



Below is a list of documentation corresponding to the Backflow Prevention Program/By-law:

Document Acrobat PDF Document Date

By-Law 09-73 "Backflow Prevention By-Law"

pdf By-Law 09-73


Process Flow Charts

pdf Backflow Prevention Program Process - Device Installation - rev1
pdf Backflow Prevention Program Process - Annual Test and Inspection



Cross Connection Control Survey Forms

pdf Backflow Part 1: General
pdf Backflow Part 2: Additional Cross Connections
pdf Backflow Part 3: Dental Office
pdf Backflow Part 4: Restaurant
pdf Backflow Part 5: Mortuary or Morgue
pdf Backflow Part 6: Hospital/Nursing Home


Device Testing and Inspection Reports

pdf Backflow Testing and Inspection Report - DCVA and PVB
pdf Backflow Testing and Inspection Report - RP
Town of Grimsby Plumbing Permit (Building & Enforcement Dept.)

pdf Plumbing/Sewer Permit


Upcoming Events