Compliance Guide
Backflow prevention regulations by town
Backflow rules around Toronto are set by your municipality or region. Here’s who administers the program and what’s required, town by town.
While backflow prevention exists everywhere to protect the public water supply, the specific bylaw and administering authority depend on where your property is. In the GTA, some cities run their own programs (most of York Region), while others are administered at the regional level (Peel, Durham, Halton). Across all of them, devices are selected under the CSA B64.10 standard and annual testing is the norm.
The table below summarizes the program for each town we serve. Always confirm current details with your municipality — bylaws and timelines can change.
| Town | Administered by | Bylaw / program | Testing |
|---|---|---|---|
| Toronto | Toronto Water | Water Supply By-law (Chapter 851) | Annual |
| Vaughan | City of Vaughan | By-law 177-2020 | Annual |
| Markham | City of Markham | By-law 2012-29 | Annual |
| Richmond Hill | City of Richmond Hill | By-law 125-14 | Annual |
| Aurora | Town of Aurora | Backflow & Cross Connection By-law 6213-19 | Annual |
| King City | Township of King | Cross Connection Control Program | Annual |
| Mississauga | Region of Peel | Peel Backflow Prevention By-law (2017) | Annual |
| Brampton | Region of Peel | Peel Backflow Prevention By-law (2017) | Annual |
| Bolton | Region of Peel | Peel Backflow Prevention By-law (2017) | Annual |
| Oshawa | Region of Durham | Durham Backflow Prevention Program | Annual |
| Pickering | Region of Durham | Durham Backflow Prevention Program | Annual |
| Oakville | Halton Region | Halton Cross-Connection Control Program | Annual |
| Barrie | City of Barrie Water Operations | By-law 2017-121 | Annual |
How the regions differ
York Region — municipal bylaws
Cities in York Region generally run their own programs: Vaughan (By-law 177-2020), Markham (By-law 2012-29), Richmond Hill (By-law 125-14), Aurora (By-law 6213-19), and the Township of King. Requirements and rollout timelines vary by municipality.
Peel Region — regional program
Mississauga, Brampton, and Caledon (including Bolton) fall under the Region of Peel’s backflow prevention by-law. Owners may receive a mailed notice to complete a cross-connection survey within 60 days, with device installation and annual testing following.
Durham & Halton — regional programs
Oshawa and Pickering are administered by the Region of Durham; Oakville is administered by Halton Region. Both run cross-connection control / backflow prevention programs requiring annual testing of eligible properties.
City of Toronto & City of Barrie
Toronto enforces backflow prevention through its Water Supply By-law (Chapter 851) via Toronto Water. Barrie runs its own program under By-law 2017-121 and requires a Qualified Person registered with the City.
Find Your City
Local backflow testing across the GTA
Vaughan
Testing in VaughanMarkham
Testing in MarkhamRichmond Hill
Testing in Richmond HillAurora
Testing in AuroraKing City
Testing in King CityMississauga
Testing in MississaugaBrampton
Testing in BramptonConfused about your town’s requirements?
We know the local programs across the GTA. We’ll confirm what applies to your property and handle compliance.