Test procedure
- 1Identifyrecord the assembly type, size, make and serial number
- 2Isolatewarn occupants, then close the shut-offs on either side
- 3Testrun the gauge across each check and the relief valve to read the pressure differentials
- 4Repairclean or replace failed checks, springs and seats, then retest
- 5Reportcomplete the test record and hand over a copy for the building file
01Why the test matters
When the street main loses pressure, say during a break or a big fire call, water inside a building can try to run backwards. A boiler loop full of treatment chemicals, a carbonation line in a restaurant or an irrigation system on a plaza lawn can all push contaminated water toward the street if nothing stops it. The assembly stops it, but only while its internal checks still seal.
- Rubber and springs age.
- Debris from a main repair can lodge under a seat.
- The only way to know the device still works is to put gauges on it.
| Where you find them | Mechanical rooms, water entry points, fire lines, boiler and irrigation feeds |
|---|---|
| Common assemblies | Reduced pressure principle (RP) and double check valve (DCVA) |
| City program | Toronto requires testing of premise isolation devices; check current terms and deadlines |
02Signs an assembly needs attention
Some faults are obvious before the test date comes round:
- The relief port on an RP assembly dribbling or dumping water
- Water on the mechanical room floor under the device
- A test tag that is missing or more than a year old
- Pressure loss in the building after a city main repair nearby
- A new tenant whose use, such as a lab or a kitchen, raises the hazard level
03Repairs and replacements
Most failed tests are fixed with a repair kit: new discs, springs or relief valve parts fitted while the assembly stays in the line. Older units whose parts are no longer stocked, or that were installed where nobody can reach the test cocks, are better replaced. A replacement needs a permit and must be placed so the next tester can work on it safely; we plan that with you before ordering parts.
Water to the building is off only for the minutes the device is isolated. On occupied buildings we post notice on the doors first.
Questions and answers
Is yearly backflow testing required in Toronto?
The City of Toronto program generally requires testing on installation and at least once a year after that. Check the current program terms for your property.
What happens if my assembly fails the test?
It is usually repaired on the spot with a parts kit and retested. If it cannot be repaired, it has to be replaced, and the test record reflects that.