Backflow Prevention Testing & Certification

Backflow is water travelling the wrong way through a building's plumbing, back toward the drinking water supply. It matters because the water heading backwards may have picked up something on the way: boiler treatment chemicals, irrigation runoff, cooling tower water or anything else the building's systems contain. A backflow preventer is a mechanical assembly, normally installed on the incoming main and at each higher-risk connection, that allows water through in one direction and physically blocks it from returning.

Yes. The City of Toronto operates a backflow prevention programme under its water supply by-law, which requires owners of industrial, commercial, institutional and multi-residential properties to survey their buildings for cross-connections, install appropriate premise isolation, and have the devices tested by a certified tester on a recurring basis, normally annually, with the report submitted to the City. Other GTA municipalities run comparable programmes under their own by-laws. We handle the testing and the filing.

The City follows up on overdue reports, and the escalation path runs through notices to enforcement and, in principle, to interruption of the water service. In practice the more immediate consequences arrive sooner: insurers ask about it, engineers note it in building condition assessments, and it appears as a deficiency in status certificate enquiries. It is an inexpensive item to keep current and a conspicuous one to have outstanding.

Because a high-rise is not only residences. The building has a heating loop with treated water in it, make-up connections to that loop, very often irrigation, sometimes a cooling tower, a garage wash bay, a pool or spa, and janitorial sinks with hose connections. Each of those is a point where non-potable water sits at a pressure that could push back toward the supply. The residential suites are precisely what the protection exists to protect.

Two ways. Backsiphonage occurs when the supply pressure drops below the pressure in the building, which happens during a water main break, a large fire-fighting draw or upstream maintenance, and the line siphons backwards. Backpressure occurs when something inside the building pushes harder than the supply, which is the normal condition downstream of a booster pump set, a boiler circuit or an elevated heating loop. A high-rise routinely has both mechanisms present.

Testing any device means isolating it for a few minutes. For the in-premise devices that affects only the system it serves, such as irrigation or boiler make-up, and residents notice nothing. For premise isolation at the incoming main it does briefly affect the building, so it is scheduled with management, notified in advance and kept as short as possible. We sequence the visit so the interruption is minutes rather than hours.

No. Backflow devices are common element equipment and live in mechanical rooms, the garage, the irrigation room and similar service spaces. There is no suite access required for this work at all. The only thing a resident may notice is a short, notified interruption to the building supply if the premise isolation device is being tested that day.

A certified tester connects a calibrated differential pressure gauge to the test cocks on the assembly and works through the procedure defined for that device type. On a reduced pressure assembly that means verifying each check valve holds tight against reverse flow and that the relief valve opens at the correct differential. The readings are recorded on the report as taken. It takes minutes per device where the assembly is accessible and passes first time.

It has to be repaired or replaced and then retested, and a failed device is a real finding rather than a formality. Most failures are a fouled seat, a perished rubber disc or a weak spring, and we carry repair kits for the common assemblies so it is rebuilt on the same visit. Where the body is eroded, the device is obsolete or it is the wrong device for the hazard, we quote replacement and report the condition.

A reduced pressure assembly has a relief port underneath that is designed to discharge if either check valve stops holding. An occasional brief discharge during a pressure fluctuation is normal. A continuous or repeated discharge is the device telling you it has failed and is doing its job by dumping to atmosphere rather than letting anything back into the supply. Report it, do not plug it, and make sure the drain beneath it stays clear.

It can and should be directed to an air gap over a suitable drain, which is a normal part of a correct installation. It must never be capped, plugged or connected directly into a drain line. The relief port is the safety function of the device, and defeating it converts an assembly that protects the building into one that cannot. Where we find a capped or improperly terminated relief, it is recorded as a correction.

A reduced pressure assembly has two independent check valves with a relief valve between them, so if either check fails, the intermediate zone dumps to atmosphere and nothing gets back to the supply. A double check assembly has the two checks but no relief, which makes it simpler but means a failure is not self-announcing. The reduced pressure type is required where the hazard downstream is severe; the double check is used for moderate hazards. Matching the device to the hazard is the part that gets missed.

In a condominium, backflow protection is common element equipment on common element piping, so responsibility sits with the corporation and the cost falls under common expenses. Where an individual unit has had something installed that creates a cross-connection, for instance an unprotected hose connection or an unusual appliance, that specific protection may fall to the owner. In practice the survey identifies these and management resolves them case by case.

Yes, and it is the part boards most want off their desk. We complete the report for each device, submit it on the corporation's behalf, provide a copy for the building record, and diarise the next test date so we return on schedule. Management does not have to track renewal dates, chase a tester or field an overdue notice.

With the survey, because you cannot test a device nobody has identified and you cannot protect a connection nobody has found. We walk the building, document every existing device and every point requiring protection, assess the degree of hazard at each, and produce a schedule showing what is compliant, what needs a device and what has the wrong device fitted. From there the corrections can be planned and budgeted rather than discovered during an inspection.

The assemblies are long-lived, and with annual testing and periodic rebuilds many run for decades. What wears is the internals: seats, discs, springs and O-rings, and those are serviceable items replaced during a rebuild. Replacement of the whole assembly becomes the right answer when the body is eroded, the model is obsolete and parts are no longer available, or the device was never correct for the hazard it sits on.