Backflow Testing Frequently Asked Questions

Common Questions



  • Why do I need a "Backflow Prevention Assembly" on my Sprinkler Irrigation System?
  • The  water that is used by your irrigation system is supplied by the same  source as the water you drink, cook and bathe with. Pesticides, fertilizers and/or animal feces can collect in water pooled around your sprinkler heads, creating a potential for the contaminants to be drawn  back through the sprinkler irrigation system (by means of Backflow or back-siphonage) and into your home.  It is for this reason that you must have a properly functioning Backflow Prevention Assembly protecting your drinking water.
  • Why do I need my "Backflow Prevention Assembly" tested annually?
  • Backflow Prevention Assemblies and Devices break or wear out, just like the  parts of a car. By having your Backflow Prevention Assembly tested annually, you will help to ensure that the drinking water supplied to your home remains safe. Because of this many lower mainland cities have created this By-law to help insure the safety of your drinking water. We have Certified Backflow Assembly Testers on staff who have attended  rigorous training, and are certified by the American Backflow Prevention Association (ABPA). Certified Testers can inspect, test, repair or replace all Backflow Prevention Assemblies and Devices.
  • Why have I never had to test my Backflow before?

    When your Backflow was installed it was tested prior to the plumbing  inspection, but because of the volume of Backflow assemblies being installed and the large number of existing Backflow assemblies in various lower mainland cities it is not easy for municipalities to keep you informed of when your Backflow is due to be tested. However, due to increased awareness of the importance of protecting our water, many cities are taking better steps to inform people when their annual test is due.
  • What is a cross-connection?

    A cross-connection is any temporary or permanent connection between a public water system or consumer's potable (i.e., drinking) water system and any source or system containing non-potable water or other substances. An example is the piping between a public water system or consumer's potable water system and an auxiliary water system, cooling  system, or irrigation system.

  • What is a Backflow preventer?

  • A  Backflow preventer is a means of mechanism to prevent Backflow.  The basic means of preventing Backflow is an air gap, which either eliminated a cross-connection or provides a barrier to Backflow. The basic mechanism for preventing Backflow is a mechanical Backflow preventer, which provides a physical barrier to Backflow. The principal  types of mechanical Backflow preventers are the reduced-pressure  principle assembly, the pressure vacuum breaker assembly, and the double  check valve assembly. A secondary type of mechanical Backflow preventer  is the residential dual check valve.
  • What is an air gap?
  • An  air gap is a vertical, physical separation between the end of a water  supply outlet and the flood-level rim of a receiving vessel. This  separation must be at least twice the diameter of the water supply  outlet and never less than one inch. An air gap is considered the  maximum protection available against back pressure Backflow or  backsiphonage, but is not always practical and can be easily bypassed.
  • What is a reduced principle (RP) assembly?
  • An  RP is a mechanical Backflow preventer that consists of two  independently acting, spring-loaded check valves with a hydraulically  operating, mechanically independent, spring-loaded pressure differential  relief valve between the check valves and below the first check valve.  It includes shutoff valves at each end of the assembly and is equipped  with test cocks. An RP is effective against back pressure and  backsiphonage and may be used to isolate health or non-health hazards.
  • What is a pressure vacuum breaker (PVB) assembly?
  • A  PVB assembly is a mechanical preventer that consists of an  independently acting, spring-loaded check valve and an independently  acting, spring-loaded, air inlet valve on the discharge side of the  check valve. It includes shutoff valves at each end of the assembly and  is equipped with test cocks. A PVB may be used to isolate non- health  hazards, but is effective against backsiphonage only.
  • What is a double check valve assembly?
  • A  DCVA is a mechanical Backflow preventer that consists of two  independently acting, spring-loaded check valves. It includes shutoff  valves at each end of the assembly and is equipped with test cocks. A DC  is effective against back pressure Backflow and backsiphonage but  should be used to isolate only non- health hazards.
  • How much will the test cost and does the City Charge a fee for Backflow testing?
  • Our Price is $30 per test for assemblies up to 4" and $450 for 4.5" and above.  Look at our home page  for any “Specials” that we might have.  Typically, other companies will  charge $35-$50 or more for the same service so act now and get your  assembly test scheduled with us!