There is no backflow season. Your test is due 12 months after the last pass, and the report goes to a different authority depending on the municipality. Here is how to keep every device on schedule.
If you manage more than one building, there is probably a spreadsheet somewhere with backflow dates in it, and at least one of those dates is wrong. The confusion usually comes from one assumption: that the City has a backflow season. It does not.
Quick answer
- Your backflow test is due 12 months from the date of the last passing test, not on a fixed calendar date.
- A new or replaced device is tested at installation. In Toronto, a device that is cleaned, repaired, replaced, serviced or overhauled is retested within 72 hours.
- Each device is tested and reported individually, so one building can have several due dates.
- Reports go to the city or town for Toronto, Vaughan, Markham, Richmond Hill, Aurora, King City and Barrie, and to the Region for Mississauga, Brampton, Bolton, Oshawa, Pickering and Oakville.
- Testing every device in one visit aligns the dates and lowers the per-device price.
When is my backflow test due?
Twelve months after the last passing test. If your device passed on the 10th of a month, the next test is due by the 10th of the same month next year, and the municipality counts from the date on the filed report, not from when you booked.
That is why two neighbouring buildings owned by the same company can have due dates six months apart. Each one started its clock on the day it was first tested.
The Toronto Water Supply By-law and the by-laws in the surrounding municipalities all use the same 12-month cycle, so the rule travels with you across the GTA.
What else triggers a backflow test besides the annual date?
Three events add to your schedule: installation, service work and a City notice. Each of them produces a test report that starts a fresh 12-month clock for that device.
- Installation. Every new or replacement device is tested before it goes into service, and the report filed. See backflow preventer installation.
- The 72-hour rule. In Toronto, a device that is cleaned, repaired, replaced, serviced or overhauled must be retested within 72 hours. A failed annual test that leads to a repair therefore produces two reports in one week.
- A survey or notice. If a cross-connection control survey or a compliance notice identifies a device, the deadline on the notice governs, regardless of where you are in the annual cycle.
Why the 72-hour rule matters for planning: if a device fails late on a Friday afternoon, the repair and retest need to happen early the following week. Book repairs with a company that can test the same day; our repair and replacement service includes the retest.
Where does the backflow report go in each municipality?
In Toronto, the York Region municipalities and Barrie the report goes to the city or town itself; in Peel, Durham and Halton it goes to the regional authority that runs the water system. Your tester files it, but you should know who holds the record.
| Municipality | Authority and program | Where the report goes |
|---|---|---|
| Toronto | Toronto Water, Water Supply By-law (Chapter 851) | City of Toronto online test report form |
| Vaughan | City of Vaughan backflow prevention by-law | City of Vaughan |
| Markham | City of Markham backflow prevention by-law | City of Markham |
| Richmond Hill | City of Richmond Hill backflow prevention by-law | City of Richmond Hill |
| Aurora | Town of Aurora backflow prevention by-law | Town of Aurora |
| King City | Township of King cross-connection control program | Township of King |
| Mississauga, Brampton, Bolton | Region of Peel Backflow Prevention By-law | Region of Peel |
| Oshawa, Pickering | Region of Durham backflow prevention program | Region of Durham |
| Oakville | Halton Region Cross-Connection Control Program | Halton Region |
| Barrie | City of Barrie Water Operations by-law | City of Barrie |
The by-law numbers for each municipality, and what each program expects of owners, are in our Ontario backflow regulations by town guide.
Managing several sites? We can test every device across your portfolio on one schedule, file each report with the right authority and send one reminder next year — $350 for a single device, as low as $200 per device on larger sites. Get a fixed quote or call (647) 578-9903.
How should multi-site managers plan backflow testing?
Build a device register, align all the devices on a property to one test date, and set the reminder from the report date rather than from memory. Four habits keep a portfolio compliant without much effort:
- Keep a register with the address, device location, type, serial number, last test date and the authority that holds the report.
- Test every device on a property in one visit, even if some are a month or two early. The dates line up and the per-device price drops.
- Set a reminder at 10 months so there is time to book, fix and retest before the 12-month mark passes.
- Store every filed report in one shared folder; a City notice is closed by forwarding the report, not by explaining.
Backflow Inspector, a service of MT Drains & Plumbing, keeps this register for its clients and sends the reminder before each device falls due.
What happens if I miss the backflow test deadline?
The property becomes non-compliant on the day the 12 months lapse, and the municipality may issue a compliance notice with a deadline to file a passing report. Enforcement is administrative: meet the deadline and the file closes.
Ignore the notice and it escalates. The Toronto by-law provides for penalties and water-service measures for continued non-compliance, so a notice is the point to act, not to negotiate.
If a notice has already arrived, read our guide to how test report filing works and book a test for the earliest date you can give access.
Quick answers
One schedule for every device you manage
We test across your portfolio, file with the right authority in each municipality and remind you before the next due date — from $350 per device, as low as $200 on larger sites.