Backflow Prevention for Home Irrigation in Ontario
Every irrigation system tied into municipal water needs backflow protection. Here is what the requirement means for homeowners.
What backflow is and why it matters
Backflow happens when pressure in the municipal line drops, for example during a water main break or heavy hydrant use, and water is drawn backwards out of your irrigation piping into the drinking water supply. That water has been sitting in pipes in contact with soil, fertilizer and pet waste.
The device that prevents it
Residential irrigation in Ontario is typically protected by a double check valve assembly or a pressure vacuum breaker, installed downstream of the isolation valve and upstream of the zone valves. Municipalities across the GTA require an approved device on any permanent connection, and several require periodic testing by a certified tester.
Signs your protection needs attention
- Continuous weeping or spitting from the device
- Visible corrosion, cracks or frost damage after winter
- A device installed below grade in a valve box, which many current standards do not accept
- No record of testing on a property you recently purchased
Maintenance and winter
The assembly is the most freeze-vulnerable component in the entire system. Every fall it must be isolated, drained and left with test cocks partially open. Every spring it should be inspected before the mainline is charged.
What we do
Every installation we perform includes a code-appropriate backflow assembly, properly located and documented. On service visits we inspect the device and note its condition in your written report so you have a record if your municipality requests one.
Requirements vary by municipality. Confirm the exact rule with your local water department or ask us and we will point you to the current bylaw for your city.