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:
- High Risk - Reduced Pressure Zone Assembly (RPZA) – must be tested annually
- Moderate Risk - Double Check Valve Assembly (DCVA) – must be tested annually
- Low 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.
Air Gap (AG)
The vertical distance between the end of a water supply outlet (i.e. a hose, a tap) and the vessel or container the water is discharged into.
Reduced Pressure Zone Assembly (RPZA)*
Two independently acting check valves separated by a reduced pressure zone.
Double Check Valve Assembly (DCVA)*
Two internally loaded check valves, force-loaded or internally weighted.
Hose Connection Vacuum Breaker (HCVB)
A spring-loaded check valve seals against an atmospheric outlet when the water supply is turned on.
Dual Check Valve (DuC)
Two independently acting, spring loaded check valves.
* Only the Reduced Pressure Principle Assembly (RPZA) and the Double Check Valve Assembly (DCVA) will be accepted for Premise Isolation.
Premise Isolation is having a backflow prevention device installed at the point where the water service enters a property, building or facility.
The following properties are required to have Premise Isolation at the property line:
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.
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 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 high hazard category, you will need to update to Premise Isolation.