Backflow prevention is one of those invisible parts of plumbing that nobody thinks about until they get a non-compliance letter from Sydney Water. If you run a café, gym, medical practice, strata block, irrigation system or rainwater-connected home in Shellharbour, Wollongong or Kiama, you almost certainly have a testable backflow device — and you're required to have it tested annually by a licensed plumber with a backflow endorsement.
What is backflow prevention?
Drinking water in NSW flows in one direction: from the Sydney Water main to your taps. Backflow is what happens when that direction reverses — usually because of a sudden pressure drop in the mains (a burst nearby, a hydrant being opened) sucking contaminated water from your premises back into the public supply. A backflow prevention device is a one-way valve designed to make that physically impossible.
Where backflow devices are required
- Commercial premises (cafés, restaurants, medical, dental, salons, gyms)
- Industrial sites with chemical use, wash bays or trade waste
- Strata buildings and multi-unit residential
- Properties with rainwater tanks connected to the house plumbing
- Irrigation systems with fertiliser or chemical injection
- Fire services on commercial premises
Annual testing — what's involved
Testable backflow devices (medium and high hazard) must be tested annually by an accredited plumber. The test takes around 30 minutes per device and involves isolating the device, attaching a calibrated test kit, and verifying the check valves and relief valve all function within tolerance. Results are lodged directly with Sydney Water via their backflow register.
Common failures we find on Illawarra devices
- Debris in the check valve seat — usually pipe scale from the main
- Perished rubber on the relief valve diaphragm (typical after 5–7 years)
- Damaged downstream check from water hammer
- Devices installed below the required height above flood level
- Devices installed without a strainer, dramatically shortening lifespan
Where a device fails the test, we'll quote a repair on the spot. Most can be rebuilt with a service kit. Older devices that have failed multiple times often get swapped out for a current-model RPZ valve, which is more reliable and easier to service.
What happens if you don't test?
Sydney Water issues reminders, then non-compliance notices, then financial penalties. Worse — if an incident happens upstream and your untested device is implicated in a contamination event, you carry significant liability. The annual test is cheap insurance and we lodge directly so you don't deal with the paperwork.
Booking your test
Our backflow technician services Shellharbour, Wollongong, Kiama and the surrounding Illawarra LGAs. We'll send you a reminder before your test is due each year, attend on the agreed date, lodge the certificate, and email you a copy for your records.
Frequently asked questions
- How often does a backflow prevention device need to be tested?
- Medium and high hazard testable devices in NSW must be tested every 12 months by an accredited plumber. Low-hazard devices (single check valves) typically don't require testing.
- Who can test a backflow device in NSW?
- Only a plumber accredited with the relevant backflow endorsement and approved test kit can lodge a valid test report with Sydney Water. We hold the endorsement and lodge results directly through Sydney Water's online register.
- What happens if my backflow device fails the test?
- We isolate the device, quote you a rebuild with the manufacturer's service kit, complete the repair (usually the same visit), then retest and lodge a passing certificate. Most devices can be rebuilt rather than replaced.
- Do I need a backflow device on a rainwater tank?
- Yes — if the rainwater tank is connected to anything downstream of the Sydney Water mains in the same property (toilet, laundry, hot water, anywhere), you need a backflow device on the mains connection. It protects the public supply from rainwater contamination.
- How much does annual testing cost?
- We keep it competitive — get in touch with the device type and we'll quote on the spot. Most single-device tests in Shellharbour, Wollongong or Kiama can be done in one short visit.