Where you will find one
- Just inside the wall where the city service enters a plaza, office or industrial unit
- On fire sprinkler connections
- On boiler feeds, irrigation systems and chemical dispensers
- On lines feeding commercial kitchens, labs, car washes and medical offices
The common device types
- Reduced pressure zone (RPZ): two check valves with a relief valve between them, used where the hazard is higher.
- Double check valve assembly: two independent checks, used for lower-hazard connections.
- Dual check and vacuum breakers: smaller devices on individual fixtures and hose connections.
What a test visit includes
- Arrange the shutdown. We agree a time when a short water interruption will cause the least trouble.
- Connect the test kit. A differential pressure gauge goes onto the device’s test cocks.
- Check each part. Each check valve and the relief valve is tested against its required pressure differential.
- Repair if needed. Failed checks or relief valves are rebuilt with the manufacturer’s kit, then retested.
- Record the results. The readings go onto the test report your municipality or water purveyor expects.
Local requirements
Ontario cities, Vaughan included, use by-laws calling for backflow assemblies on many non-residential and multi-unit properties, tested on a schedule, with the paperwork filed with the municipality. Testing intervals, device requirements and submission methods belong to the City and are revised now and then, so check the current terms directly with Vaughan before you plan the year. Keep copies of every test report on site.
Signs a device is in trouble
- Water discharging from the RPZ relief port between tests
- Low pressure throughout the building since a device was installed
- Green crust or weeping around the test cocks and the gate valves
- An assembly whose last test tag is more than twelve months old
Call to book a test or to have a dripping relief valve looked at.
Building types and the plumbing we handle
| Property | Typical work | More |
|---|---|---|
| Restaurants & food courts | Interceptors, floor sinks, pre-rinse units | Read more |
| Offices & plazas | Flush valves, washrooms, small tank heaters | Read more |
| Condo & rental buildings | Risers, stacks, booster and sump pumps | Read more |
| Any metered service | RPZ and double check valve testing | Read more |
| Main and building drains | Jetting with before-and-after camera | Read more |
Before we book
- Opening hours and quiet windows
- Who approves the work
- Location of the main shut-off and cleanouts
- Any inspection or report deadlines
What you receive afterwards
- Written summary of the work
- Photos or camera footage where useful
- Test reports where a test was done
- Follow-up work listed separately
Quick answers
Why is my RPZ dripping?
A small discharge from the relief port often means the first check valve is not sealing, or pressure is fluctuating. It should be tested and repaired rather than plugged.
How long does the water need to be off?
Usually only for the test itself, often well under an hour per device, unless repairs are needed.