Accepted Backflow Prevention Assemblies

Backflow prevention devices, if properly installed and maintained, allow water to flow in only one direction. Water can flow from the public water system to the customer's property, but not in the other direction.

The type of device that is suitable for your property is based on the degree of hazard your property presents to the public water system. The most common types of backflow devices used are:

  • Severe Risk - Reduced Pressure Backflow Assembly (RPBA) – must be tested annually
  • Moderate Risk - Double Check Valve Assembly (DCVA) – must be tested annually
  • Minor Risk - Dual Check Value – not testable

Types of Backflow Prevention Devices

If you are required to install a backflow preventer, contact the City of Pitt Meadows for recommendations on which preventer to install.

Reduced Pressure Backflow Assembly (RPBA)*

Two independently acting check valves separated by a reduced pressure zone.
Installed as a unit between two shut off valves.
Each check valve is fitted with a test cock for periodic testing.
Can be used for health hazards (i.e. toxic material) and severely hazardous connections (i.e. medical/dental facilities, industrial plants and agricultural operations).

Double Check Valve Assembly (DCVA)*

Two internally loaded check valves, force-loaded or internally weighted.
If one check valve fails to close the other will prevent backflow.
Each check valve is fitted with a test cock for periodic testing.
Can be used for all non-health hazards (non-toxic) connections (i.e. fire sprinkler, irrigation systems).

Dual Check Valve (DCV)

Two independently acting, spring loaded check valves.
Usually does not have shutoff valves and may or may not be equipped with test cocks.
Should only be used to isolate non-health hazards and is intended for single family homes with no or minor potential hazards or risks. This device is not testable.

* Only the Reduced Pressure Backflow Assembly (RPBA) and the Double Check Valve Assembly (DCVA) will be accepted for Premise Isolation backflow devices.

Premise Isolation
Premise Isolation is having a backflow prevention device installed at the point where the water service enters a property. This provides the proper level of protection from the property, reduces the potential of bypass connections and provides consistency.

The following properties are required to have Premise Isolation at the property line:

  1. Industrial
  2. Commercial
  3. Institutional
  4. Agricultural

Already have Premise Isolation?
If your property already has Premise Isolation installed, you are required to test existing backflow prevention devices on an annual basis.

The specific type of premise isolation backflow preventer (i.e., RPBA or DCVA) will depend on the hazard associated with the property use. Contact the City of Pitt Meadows for the requirement on which preventer to install.

Fixture Isolation
Fixture Isolation is having a backflow prevention device installed at the source of the potential contamination. This provides protection for only a section of the piping system.

Zone Isolation
Zone Isolation is having a backflow prevention device installed that protects the rest of a building from one particular area.

If your property only has Fixture or Zone Isolation, and you fall into the severe or moderate hazard category, you will need to upgrade to Premise Isolation.

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