Backflow prevention device testing
The short answer
Every testable backflow prevention device protecting the drinking water supply must be tested every 12 months by an accredited or endorsed plumber, to AS/NZS 2845.3. The results go to the water authority, and the owner keeps a copy.
Who has to have it done
The property owner carries the obligation, imposed by the water authority. In practice the plumber is engaged by the owner, the facility manager or the body corporate. It applies to effectively every commercial site with a testable device: fire services, irrigation systems, cooling towers, medical and dental suites, car washes, and anything else the authority has assessed as a hazard to the drinking water supply.
What the test actually involves
The device type drives the test. For an RPZD or double check valve you are recording mains pressure, whether the upstream and downstream isolating valves hold tight, the differential across check valve one, the pressure the relief valve opens at, and check valve two. For vacuum breakers it is the non-return valve and the pressure the air inlet opens at. Every one of those is a number, not a tick, and the number is what the authority form wants.
Submitting to the water authority
This is the part that catches people. Your report is your own record and the client copy, but it does not replace the submission. Test results must go to the relevant water authority, typically within 20 days of the test, and several now use online portals. Each authority has its own form, but because the test content is identical under AS/NZS 2845.3, the readings map straight across from your own record.
When a device fails
A failed device has to be repaired and retested, generally within 20 business days. Victoria sets that out in the Water (General) Regulations 2021 and most other authorities work to something similar. The retest is a fresh test report, not an amendment to the failed one.
Who is responsible for what
The property owner is obliged by the water authority to have devices tested annually. The testing must be done by a plumber with the appropriate backflow accreditation or endorsement, using a test kit with a current calibration date. The tester keeps a record, the owner keeps a copy, and the authority gets the submission.
What the report should record
- Property address and the water authority property or service number
- Device make, model, size in mm, and serial number
- Device location on site, described well enough that the next tester can find it
- Hazard rating (high, medium or low) and protection type (containment, zone or individual)
- Type of test: commissioning, annual, replacement, repairs or decommission
- Every pressure reading in kPa, not just a pass or fail
- Test kit serial number and the date it was last calibrated
- Tester name, licence or registration number, and the date and time of test
- Overall pass or fail, with the declaration that the test was done to AS/NZS 2845.3:2020
What commonly goes wrong
- Test kit calibration out of date, which invalidates every reading taken with it
- Recording pass or fail without the actual kPa figures, so the authority form cannot be completed from the record
- Devices installed where they cannot be accessed for testing, contrary to AS/NZS 3500.1
- Missing isolating padlocks or handle locks
- A failed device repaired but never retested inside the 20 business day window
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Common questions
How often do backflow devices need testing in Australia?
Every 12 months from the date of the last test, plus a commissioning test on new installations and after any repair or replacement.
Who can test a backflow prevention device?
A plumber holding the relevant backflow accreditation or endorsement, using a test kit with current calibration.
Does the test report have to go to the water authority?
Yes. Typically within 20 days of the test, often through the authority's online portal. Your own report is the record and the client copy, not a substitute for that submission.
What happens if a device fails the test?
It must be repaired and retested, generally within 20 business days. The retest produces a new test report.
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Last reviewed: September 2026. General information for tradespeople, not legal advice. Standards and regulations change. Governing references for this page: AS/NZS 2845.3:2020; AS/NZS 3500.1; state water regulations and water authority backflow policies. Confirm the current position with your local water authority before you rely on it.