Backflow Testing & Prevention
Tested, tagged and signed off.
Annual backflow testing for your building WOF
If your building has a backflow prevention device, it needs testing every year by an independent qualified person (IQP) before you can renew your building warrant of fitness (BWOF). Schools, early childhood education (ECE) centres, shops, offices, cafes and workshops often have one, and sometimes more than one.
Aqua Works tests, repairs and installs backflow prevention devices across Rodney and North Auckland. Our IQP signs off every test. You get a signed test report and the Form 12A for your building WOF, and we remind you before the next test is due.
Watercare asked you to test the backflow device on your irrigation meter or fire sprinkler connection? We test those too.
Tested, tagged and signed off by our IQP.
Testing, repairs and new devices
A backflow prevention device stops dirty water flowing back into the drinking water supply. It only does its job if it’s tested and looked after.
Annual backflow testing
We test each device with a calibrated test kit, to the New Zealand backflow testing standard, and check it’s still the right device for the hazard it protects against. A device has to be tested after it’s installed, after any repair, and then at least every 12 months.
Signed off by our IQP
Our IQP is registered with the council for backflow preventers (specified system SS7), and two of our team have completed the NZQA backflow testing training. Our IQP signs the test report and the Form 12A for every device we test.
If a device fails
We tell you why, and we aim to repair and retest it on the same visit. A failed device can’t be signed off until it passes.
New devices
Our certifying plumbers install new backflow prevention devices, from testable double check valves to reduced pressure zone devices (RPZ). Our IQP then tests and signs off each one.
Your paperwork
You get a signed test report every time, pass or fail, and a Form 12A to go with your building WOF. Keep them with your compliance schedule: the council can ask to see the last two years.
Homes with a Watercare device
A house doesn’t need a building WOF. But if Watercare has fitted a testable backflow device to your irrigation meter or fire sprinkler connection, it still needs testing every year, and Watercare wants the certificate. If it doesn’t get one, it arranges a test and sends you the bill.
Every test includes
Device and location recorded.
Tested with a calibrated kit.
Checked against the hazard.
Valves and strainer checked.
An Aqua Works tag on the device.
A signed report, pass or fail.
A Form 12A for your building WOF.
A price for any repair.
A reminder before the next test.
Our tag goes on every device we test. The back keeps a record of each test, so anyone checking the device can see its history.
Who needs a backflow test?
- Buildings with a backflow preventer on the compliance schedule.
- Schools and ECE centres.
- Shops, offices, cafes, restaurants and workshops.
- Medical, dental, beauty and hair businesses.
- Sites with fire sprinklers or irrigation.
- Homes with a Watercare irrigation or sprinkler device.
Where backflow comes from
- A pressure drop in the main, from a burst or firefighting.
- Pumps, boilers and bores pushing water back.
- Hoses left in buckets, troughs, tanks or pools.
- Chemical dosing, dispensers and spray mixing.
- Irrigation and fire sprinkler systems.
Backflow test due? Talk to us.
Local Jobs – Local Trust – Local Experts
Recent backflow jobs
From backflow jobs around Rodney.
Omaha Flats: the yearly test on an RPZ in a pump shed, for the building WOF. That’s the relief valve opening during the test, right on cue. It passed.
Warkworth: a double check valve above the sink in a commercial kitchen, tested and passed.
Matakana: a leaking RPZ at a clinic. The old valve was no longer made, so we fitted a new Watts valve and tested it.
The rules for building owners
Under the Building Act, a backflow preventer connected to a drinking water supply is a specified system (SS7). If your building has one:
- It’s listed on the building’s compliance schedule.
- An IQP inspects and tests it every year and signs a Form 12A.
- You supply your building WOF to the council every year, with the Form 12As.
- You keep the signed reports with the compliance schedule for two years.
- You display the building WOF where people can see it.
Not supplying a building WOF can mean a fine of up to $50,000 for a person, or $150,000 for a company.
Source: Building Act 2004, sections 100 to 111, read 7 November 2026.
Farms and lifestyle blocks
A house on its own tank or bore isn’t part of the building WOF system, but the Building Code still says drinking water must be protected from backflow. Stock troughs, irrigation, spray mixing and tank top-ups can all let dirty water back into the supply. Fill troughs and tanks through an air gap of at least 25 mm above the overflow, and fit at least a vacuum breaker to every hose tap. A bore or tank must never be connected straight to a town supply. We can check your setup and fit the right protection. See rural water supply.
Mangawhai and Kaiwaka
Kaipara District Council’s water bylaw needs an air gap on stock troughs and a reduced pressure zone device on non-domestic connections. Buildings in Kaipara follow the same building WOF rules as Auckland.
How often?
- After it’s installed: every new device is tested before it’s signed off.
- After any repair: retested before it goes back into service.
- Every year: at least every 12 months, for your building WOF or for Watercare.
- Non-testable devices: checked every year, and replaced if they leak or fail.
Got a letter from Watercare?
Watercare writes to owners when a boundary backflow device is due for its yearly test. You can ask Watercare to test it and pay its charge, or use an IQP of your choice. Either way, the certificate has to reach Watercare, or it will test the device and bill you. If a device fails, Watercare allows two weeks for it to be repaired and retested.
Call us and we’ll book the test and give you the certificate to send in.
How it works
Four steps to a device that’s signed off for the year.
1
Book a test
Tell us how many devices you have, where they are, and when your building WOF is due.
2
We test it
We test each device and check it suits the hazard. If one fails, we aim to fix it on the spot.
3
You get the paperwork
A signed test report, the Form 12A for your building WOF, and our tag on the device.
4
Reminders
We remind you before the next yearly test is due, so you don’t have to.
Your local backflow testers
Aqua Works has looked after homes, schools and businesses across Rodney and North Auckland since 2000, from our base in Warkworth.
- A council-registered IQP for backflow preventers (SS7).
- Two of our team trained to the NZQA backflow testing standards.
- Certifying plumbers for new devices and repairs.
- Members of Master Plumbers, and SiteWise Gold.
- 24/7 emergency call-outs.
Areas we cover
Mangawhai to Albany, including Warkworth, Matakana, Snells Beach, Wellsford, Orewa, Silverdale, Whangaparāoa, Millwater, Dairy Flat and Coatesville.
Backflow testing FAQs
What is backflow?
Backflow is water flowing the wrong way, back into the drinking water supply. It happens when the pressure in the main drops, for example during a burst main or firefighting, and water is siphoned back, or when a pump, boiler or bore pushes water back at higher pressure. It can carry bacteria or chemicals into the supply.
Does my building need a backflow test?
If your building’s compliance schedule lists a backflow preventer (specified system SS7), yes: every year, for your building WOF. Schools, ECE centres, shops, offices, cafes and workshops often have one. A house doesn’t need a building WOF, but a Watercare device on an irrigation meter or fire sprinkler connection still needs a yearly test.
How often does a backflow device need testing?
After it’s installed, after any repair, and then at least every 12 months. Non-testable devices should be checked every year and replaced if they leak or fail.
Who can test a backflow device?
An independent qualified person (IQP) registered with the council for backflow preventers (SS7). The same register covers Auckland, Kaipara, Whangārei and the Far North. Our IQP signs off every test we do.
What is a Form 12A?
It’s the IQP’s certificate that the inspection, maintenance and reporting for a specified system were done for the past 12 months. You attach it to your building WOF when you send it to the council.
What happens if my device fails?
We tell you why, and we aim to repair and retest it on the same visit. You still get a signed report. If it’s a Watercare boundary device, Watercare allows two weeks for it to be repaired and retested before it steps in.
Do you send the certificate to the council or Watercare?
We give the signed test report and certificate to you. You attach the Form 12A to your building WOF, or email a Watercare certificate to backflow@water.co.nz. We also remind you when the next test is due.
Can you install a new backflow device?
Yes. Our certifying plumbers install testable double check valves, reduced pressure zone devices (RPZ) and vacuum breakers, and our IQP tests and signs off each one. In Auckland, Watercare fits the device at the water meter itself.
Do farms and lifestyle blocks need backflow protection?
Yes. The Building Code still applies. Fill troughs and tanks through an air gap above the overflow, treat stock water with added chemicals as high risk, and never connect a bore or tank straight to a town supply.
How much does a backflow test cost?
It depends on how many devices you have and where they are. Repairs and parts are extra. Call us on 0800 278 296 for a price.
What areas do you cover?
Rodney and North Auckland, from Mangawhai to Albany, including Warkworth, Matakana, Snells Beach, Wellsford, Orewa and the Hibiscus Coast. For bigger jobs further away, give us a call.
Don’t just take our word for it…
⭐⭐⭐⭐⭐
“Excellent experience. Technician turned up on Sunday am, within 90mins of call out, which included him going to the store to pick up the parts. This was so important, as without their help the Childcare center would not have been able to open on the Monday. Thanks to Sherrie, Richard and the team.”
Barry Larman, 2025
⭐⭐⭐⭐⭐
“… January 2026: We had AquaWorks connect the house to the council water meter this week. It was good to see Troy again, he did a great job on the connection, all up and running in no time. His vast expertise spotted the need for a particular type of valve which he fitted. Lesser plumbers might have missed this detail. Superb job! …”
John Sibley, 2026
⭐⭐⭐⭐⭐
“It’s easy to support local businesses such as Aqua Works. Their prompt efficient service keeps us coming back every time.”
Matthew Keys, 2025
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Backflow test due?
Book it with Aqua Works. We’ll test it, tag it, sign it off and remind you next year.