❓ Question regarding the Water Corporation's requirement for Reduced Pressure Zone Devices (RPZDs) in Bullsbrook due to PFAS contamination originating from Defence, focusing on cost burden and necessity. The Minister provides answers and tables a risk assessment document.
AnsweredQoN 789Legislative Assembly
QuestionView source ↗
I refer to the Water Corporation's requirement to install Reduced Pressure Zone Devices (RPZDs) in the Bullsbrook area: (a) Will the Minister table
the original Water Corporation risk assessment that determined RPZDs were required for all Bullsbrook scheme
water connections; (b) Given that the project
scope disconnects all non-scheme water (bores, tanks, irrigation lines)
from household plumbing, will the Government commission and release an
updated risk assessment to clarify what contamination risk remains that
justifies RPZD installation at each property; (c) Who specifically
determined that RPZDs were necessary in Bullsbrook – was this decision
made solely by Water Corporation, or in consultation with Defence and
other agencies; (d) Why are Bullsbrook
residents being required to take on ongoing annual testing, servicing, and
eventual replacement costs for RPZDs beyond the 8-year period covered by
Defence, when: (i) the contamination originated from Defence; and (ii) the RPZDs exist to protect Water Corporation’s infrastructure rather than the residents’ private property; and (e) Can
the Minister confirm whether RPZDs are mandated in other Perth
metropolitan areas connecting to scheme water under similar circumstances,
or is Bullsbrook being subjected to a unique requirement due to PFAS
contamination and Defence’s involvement?
the original Water Corporation risk assessment that determined RPZDs were required for all Bullsbrook scheme
water connections; (b) Given that the project
scope disconnects all non-scheme water (bores, tanks, irrigation lines)
from household plumbing, will the Government commission and release an
updated risk assessment to clarify what contamination risk remains that
justifies RPZD installation at each property; (c) Who specifically
determined that RPZDs were necessary in Bullsbrook – was this decision
made solely by Water Corporation, or in consultation with Defence and
other agencies; (d) Why are Bullsbrook
residents being required to take on ongoing annual testing, servicing, and
eventual replacement costs for RPZDs beyond the 8-year period covered by
Defence, when: (i) the contamination originated from Defence; and (ii) the RPZDs exist to protect Water Corporation’s infrastructure rather than the residents’ private property; and (e) Can
the Minister confirm whether RPZDs are mandated in other Perth
metropolitan areas connecting to scheme water under similar circumstances,
or is Bullsbrook being subjected to a unique requirement due to PFAS
contamination and Defence’s involvement?
AnswerView source ↗
Answered
21 October 2025
Responded by
Minister for Water
Response time
5 days
(a) Yes. “See tabled paper, Bullsbrook Scheme Water Infrastructure Project by Department of Defence. Containment Backflow Prevention – Risk Assessment”.
(b) The project scope is limited to disconnecting bores from household plumbing, without including their decommissioning. This presents a risk of potential future reconnection of bores to household plumbing or the installation of new bores, and consequently poses an on-going risk to the scheme water system.
(c) Water Corporation has mandated the installation of high-rated backflow prevention devices—such as Reduced Pressure Zone Devices (RPZDs). This requirement aligns with the backflow provisions outlined in the National Construction Code – Volume 3: Plumbing Code of Australia and Water Corporation’s Backflow Prevention Policy. This approach ensures national consistency in containment backflow prevention management by Network Utility Operators.
(d) (i) and (ii) High-rated backflow prevention devices, such as Reduced Pressure Zone Devices (RPZDs), are classified as testable devices. These devices must be maintained, repaired if necessary, and tested at intervals not exceeding 12 months as specified in national standards (AS2845.3 – Water Supply Backflow Prevention Devices). This is also a regulatory requirement (Water Services Regulation 2013 – Regulation 43) and is the responsibility of the landowner or occupier. The Department of Defence (DoD) has committed to covering the installation and maintenance costs of RPZDs for an initial eight-year period. After this time, responsibility for ongoing obligations, including annual testing, maintenance and potential replacement, will transfer to individual households. Any questions regarding agreements between residents and the DoD should be directed to that Department.
(e) Water Corporation has had a statewide program since 2010 that requires customers to install and maintain property boundary containment backflow prevention devices. There are currently approximately 1,623 backflow prevention devices installed in high or medium risk residential properties across the State where customers have been required to install a backflow device to protect the network. Where there is high or medium risk, there is a requirement for devices to be annually maintained (as required under AS2845.3 – Water Supply Backflow Prevention Devices & Water Services Regulations 2013 – Regulation 43 ).
(b) The project scope is limited to disconnecting bores from household plumbing, without including their decommissioning. This presents a risk of potential future reconnection of bores to household plumbing or the installation of new bores, and consequently poses an on-going risk to the scheme water system.
(c) Water Corporation has mandated the installation of high-rated backflow prevention devices—such as Reduced Pressure Zone Devices (RPZDs). This requirement aligns with the backflow provisions outlined in the National Construction Code – Volume 3: Plumbing Code of Australia and Water Corporation’s Backflow Prevention Policy. This approach ensures national consistency in containment backflow prevention management by Network Utility Operators.
(d) (i) and (ii) High-rated backflow prevention devices, such as Reduced Pressure Zone Devices (RPZDs), are classified as testable devices. These devices must be maintained, repaired if necessary, and tested at intervals not exceeding 12 months as specified in national standards (AS2845.3 – Water Supply Backflow Prevention Devices). This is also a regulatory requirement (Water Services Regulation 2013 – Regulation 43) and is the responsibility of the landowner or occupier. The Department of Defence (DoD) has committed to covering the installation and maintenance costs of RPZDs for an initial eight-year period. After this time, responsibility for ongoing obligations, including annual testing, maintenance and potential replacement, will transfer to individual households. Any questions regarding agreements between residents and the DoD should be directed to that Department.
(e) Water Corporation has had a statewide program since 2010 that requires customers to install and maintain property boundary containment backflow prevention devices. There are currently approximately 1,623 backflow prevention devices installed in high or medium risk residential properties across the State where customers have been required to install a backflow device to protect the network. Where there is high or medium risk, there is a requirement for devices to be annually maintained (as required under AS2845.3 – Water Supply Backflow Prevention Devices & Water Services Regulations 2013 – Regulation 43 ).
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