Why Annual Testing is Legally Mandatory in Ontario
Backflow prevention assemblies—including Double Check Valve Assemblies (DCVA), Reduced Pressure Principle Assemblies (RPZ), and Pressure Vacuum Breakers (PVB)—contain internal mechanical springs, guide seats, and rubber check discs. Over time, mineral scale deposits, sediment buildup, water hammer shocks, and rubber fatigue compromise internal seals.
Because internal check valve leaks cannot be detected visually, Ontario municipal bylaws (including Toronto Code Ch. 851, Peel By-law 10-2017, and York By-law 2021-44) require annual field testing using NIST-traceable calibrated gauges by a certified OWWA technician.
Quick Facts
- Frequency: Every 12 months
- Reporting Window: 14 to 30 days
- Tester Requirement: OWWA Certified
- Gauge Calibration: Annual NIST
- Penalties: Up to $50,000 / day & water shut-off
Our 4-Step Certified Field Testing Process
Visual & Static Audit
Inspection of physical valve body, test cocks, shut-off valves, and thermal relief expansion systems.
NIST Gauge Differential Test
Attach calibrated differential pressure gauge to measure exact PSI thresholds across Check 1, Check 2, and Relief Valve.
On-Site Physical Tagging
Affix official municipal compliance tag directly to the device body with date, OWWA certification number, and status.
Digital Municipal Submission
Complete and file digital test certificates directly with Toronto Water, Peel, York, Hamilton, Waterloo, or London portals.
Tested Backflow Devices Comparison Table
| Device Type | Hazard Classification | Operating Principle | Typical Building Applications |
|---|---|---|---|
| RPZ (Reduced Pressure Zone) | Severe Hazard | Two check valves plus an intermediate differential pressure relief valve opening to atmosphere. | Chemical plants, commercial boilers, cooling towers, medical labs, car washes, irrigation injectors. |
| DCVA (Double Check Valve Assembly) | Low / Moderate Hazard | Two independently acting spring-loaded check valves in series between shut-off valves. | Commercial retail plazas, office buildings, Part 3 multi-res condos, non-chemical fire lines. |
| PVB (Pressure Vacuum Breaker) | Moderate / High (Back-siphonage only) | Spring-loaded loaded check valve with an independently acting air inlet valve. | Commercial landscape irrigation systems, industrial washdown risers. |
Need Annual Testing for Single Devices or Portfolios?
We offer competitive single-device rates and multi-building portfolio discounts across Toronto, Peel, York, Hamilton, Waterloo, and London, ON.
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