Once a year. Every testable backflow prevention device, meaning a reduced pressure zone valve, a double check valve assembly or a spill-resistant vacuum breaker, is registered with the water authority when it is installed and tested annually by an accredited backflow tester with a calibrated differential pressure gauge under AS/NZS 2845.3. The test certificate is lodged with the authority each year. A six-monthly visual check of the device for leaks, corrosion and tampering is recommended practice between tests.
The intervals
| Interval | What happens | Who |
|---|---|---|
| At installation | Device registered with the water authority; commissioning test and certificate. | Accredited backflow tester |
| Six-monthly (recommended practice) | Visual check of the device body, discharge port, strainer and isolation valves for leaks, corrosion and tampering. | Owner or staff |
| Annual | Test under AS/NZS 2845.3 with a calibrated differential pressure gauge; certificate lodged with the water authority and kept. | Accredited backflow tester |
| On failure | Repair or replacement before the supply is reinstated; retest and certificate. | Accredited backflow tester |
Who does it and what to keep
A licensed plumber with backflow accreditation and a gauge calibrated within the last twelve months. The certificate goes to the water authority (most accept lodgement from the tester) and a copy stays in the building's records with the device register: each device by location, type, size, serial number, hazard rating, install date and test dates. Where a customer does not lodge, the authority issues a notice and can restrict the supply.
The rule behind the interval
The water authority's customer contract and backflow policy require testable devices at connections rated medium or high hazard and set the annual test. AS/NZS 2845.3 Water supply: Backflow prevention devices, Part 3: Field testing of backflow prevention devices and verification of air gaps sets the test method. The plumbing code adopts AS/NZS 3500.1 for where devices are installed.
Common questions
Which properties need a testable backflow device?
Any connection the water authority rates medium or high hazard: commercial kitchens, plant rooms, irrigation with fertiliser injection, fire services with chemical additives, medical and industrial premises. The authority's hazard rating decides, and the device is on its register from installation.
What if the annual test is missed?
The water authority issues a notice with a deadline. If the test is still not lodged the authority can restrict or disconnect the supply, and the device is treated as failed until a certificate is produced.
Put it in the register
An interval only holds when the asset is listed with its tasks, its contractor and where the record lives. Standara's library carries this asset with the tasks above attached, so adding it to a site's register produces the year's schedule, the monthly to-do list and the completion record the auditor or insurer asks for. The fuller picture, with the neighbouring assets and the rule behind each interval, is in the Water systems testing schedule.
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- A worked example: one club's register, planner and records for a year
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