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Valves with tubing attached to a pipe
Valves and tubing on a supply pipe, similar to test-cock hookups.

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Commercial · Backflow

Backflow testing for commercial buildings

A backflow preventer is the check valve that keeps your building water out of the public main. Toronto requires many properties to have one and to test it every year.

  • RP and DCVA devices put through the annual test
  • Sticking checks and dumping relief valves rebuilt
  • Replacement assemblies sized and installed
  • Test results prepared for submission
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Which properties usually need one

  • Restaurants, food plants and commercial kitchens
  • Medical, dental and veterinary clinics
  • Buildings with fire sprinkler systems
  • Car washes, laundromats and salons
  • Multi-unit residential and mixed-use buildings
  • Sites with boilers, irrigation or chemical dosing

The City of Toronto backflow prevention bylaw sets out which properties need premise isolation and how test results are filed. The rules and submission process get revised from time to time, so ask the city what applies to your building today.

What happens during a test

  1. We locate the assembly, usually right after the water meter in the mechanical room.
  2. Water to the building is briefly shut off at the assembly. We tell you how long beforehand.
  3. Our calibrated differential gauge goes onto the test cocks with short hoses.
  4. The gauge readings for each check and the relief opening point are compared with the device specification.
  5. We write the numbers down and open the shut-offs again.

The City of Toronto backflow prevention bylaw sets out which properties need premise isolation and how test results are filed.

From the counter

If the assembly does not pass

  • Grit lodged on a check seat: flushed out and tested again
  • Hardened seats and diaphragms: swapped using the manufacturer kit
  • Relief valve dumping water: inspected for a fouled first check
  • Corroded body or obsolete model: replaced with a new assembly

Testing versus the home device

Our residential backflow page covers backwater valves and hose bib vacuum breakers for houses. This page is about the testable assemblies required on commercial and multi-unit water services. They do different jobs: a backwater valve stops sewage coming in, a backflow preventer stops your water going out.

Questions

How long is the water off?

Usually a short window per assembly. Buildings with two assemblies in parallel can often stay on water during the test.

What if our device fails?

Most failures are fixed with a repair kit on the same visit. The assembly is retested after the repair.

How the job runs

  1. You callDescribe what is dripping, backing up or cold, and the cross streets.
  2. We ask questionsAge of the building, pipe type if you know it, where the shut-off is.
  3. We open it upTrap off, clean-out open or wall cut: find the actual fault before quoting the fix.
  4. We test itOpen each tap on that run, watch the joints dry and show you what came out.