What is Back Flow Prevention?

March 12, 2019

Backflow prevention is by installation of compliant prevention devices to town water supply system to prevent contamination to our drinking supply (potable water). The most common devices that are used are Double Check Valves (DCV) and Reduced Pressure Zone devices (RPZ). There are also statutory requirement for testing of these devices to maintain compliance.

RPZ devices are installed in a property where there is deemed to be a high hazard such as wash down bays, close to the ocean, lakes and areas where there are chemicals stored.

DCV devices are installed where there is deemed to be a medium hazard such as under fire hose reels.

Low hazard devices are the vacuum breakers on hose taps and do not require testing, whereas the RPZ & DCV devices require testing every 12 months as per Australian Standards 3500 & AS2845.3.

lf during testing, an RPZ or DCV or any other testable backflow device should fail, the valve must be repaired, serviced or replaced and re-tested as per current plumbing regulations. Most new blocks of units built today will have containment devices at the boundary for fire and domestic as another level of protecting our water supply.

Most Councils are now enforcing backflow compliance, and are carrying out audits to ensure property owners maintain the devices on site and have them tested on an annual basis. Councils are also insisting that backflow endorsed plumbers note any non-compliant installations and defects on the statutory form 9s during the annual testing of the devices.

It is also the plumbers responsibility to point out any defects or non compliant issues to the property owner. lf the property owner has no desire to comply; the council will eventually take up the issue with the owner direct. This overview is only a brief outline of backflow prevention and if specific requirements for a properties backflow prevention compliance is required, please contact a backflow prevention specialist for professional advice.

This article was contributed by Rex Barnes of Barnes Backflow Testing and Solutions.