Backflow Prevention & Annual Testing
Western Australian law doesn't mess around with backflow — if you've got a commercial property, irrigation system, or just about any higher-risk connection, you need a testable device and a yearly inspection to go with it. Our Canning Vale plumbers handle installation, the annual test, and every scrap of paperwork that goes to Water Corporation. So those compliance letters stop stacking up on your desk.
You'd be surprised how many business owners and property managers never give backflow a second thought. That is, until a letter from Water Corporation lands in the mail telling them they've got to install a device. It's one of those plumbing requirements that tends to fly under the radar for most people. But here in WA, the rules are pretty clear: any property with a commercial, irrigation or higher-risk water connection needs a testable backflow prevention device installed. And that device? It has to get tested every twelve months by a plumber carrying the right endorsement. Our crew in Canning Vale looks after the whole thing end to end. We put the device in, carry out the yearly test, and lodge all the paperwork with Water Corporation on your behalf. Staying compliant without you having to lift a finger — that's the goal.
What backflow actually is
Water's meant to flow one direction — from the Water Corporation main into your property. Pretty simple. Backflow is when that direction gets reversed, and contaminated or dirty water ends up getting pulled backwards into the drinking supply. Two things cause it to happen. There's back-siphonage, which is basically when mains pressure drops suddenly (like when a water main bursts somewhere down the road). Then there's back-pressure, where something at your property actually pushes water backwards against the mains pressure.
A backflow prevention device works as a one-way barrier. Water passes through it, but there's no coming back.
And these risks aren't just theoretical. Think about an irrigation system that's pumping fertiliser into the lines. Or a commercial kitchen. Dental practice. A car wash. Fire service connection. If contaminated water got siphoned backwards into the main from any of those setups, it wouldn't only be your property dealing with the fallout. Your neighbours sharing that same water line could be drinking it too. That's exactly why WA regulations take this stuff seriously, and honestly why the rules end up covering more properties than most folks realise.
Who needs a backflow device in WA
Not every house needs a testable device, but the list of properties and connections that do — it's actually pretty broad. You probably need one if you've got:
- An irrigation or reticulation system connected to scheme water, especially with fertiliser or chemical injection
- A commercial or industrial property — offices, retail, hospitality, workshops
- A fire service connection
- Medical, dental or veterinary premises
- A property with a bore, rainwater tank or alternative water source cross-connected to mains
- Certain multi-storey or strata developments
Reticulation systems are everywhere around Canning Vale, Southern River and Harrisdale — and heaps of those bore and retic setups fall under these requirements. Not sure if yours does? We'll come have a look and give you a straight answer, no runaround. Our guide to backflow testing in WA breaks down the requirements in plain English if you want to read up first.
Annual testing and compliance
Here's the bit most people miss. Installing the device doesn't mean you're done with it. The valves and seals inside these testable backflow devices wear out over time — that's just how it goes — so WA law says they have to be tested every year to confirm they're still working properly. It has to be a plumber with the correct backflow endorsement doing the test, and the results get lodged directly with Water Corporation.
Let the test lapse or skip it altogether, and you could be looking at compliance action. More importantly though, the device that's supposed to prevent contamination might have actually stopped working. We keep tabs on when your test comes due, show up to carry it out, and handle all the reporting side of things. You stay compliant without having to diarise anything.
What the annual test involves
- Isolating and inspecting the device
- Testing the valves and seals with calibrated gauges
- Servicing or repairing the device if it fails
- Completing and lodging the compliance paperwork with Water Corporation
- Setting a reminder for next year's test
Installation done properly
Maybe you're setting up a new connection. Fitting out a reticulation system. Or you've got a compliance letter sitting there telling you a device is needed. Whatever the situation, we put in the right type of device for your particular risk level and connection. It has to be rated correctly for the hazard, positioned somewhere accessible for testing down the track, and registered the way Water Corporation wants it. Get those things wrong at the start and you're looking at years of headaches. A device wedged into some awkward corner that's a nightmare to reach every twelve months — that's a problem you really don't want to inherit from someone else.
Types of backflow device
Not all backflow devices are the same, and the one your property needs depends on the hazard rating of your connection. Lower-risk situations might only need a simple non-testable device. Higher-hazard setups — think chemical injection, medical premises, fire services — require a testable device. Something like a reduced pressure zone valve or a double check valve assembly.
Fit too little protection and you're both non-compliant and exposed. Go overboard and you've paid for something the connection doesn't actually need. We properly assess the hazard and recommend the right device first time round, so you're covered without spending more than you have to.
Sorted for commercial and irrigation
Backflow compliance doesn't sit on its own — it usually comes packaged with other plumbing requirements that commercial properties deal with. Things like tempering valves and grease traps. All of that falls under our commercial plumbing service. Manage a strata? Run a business? Look after a large irrigated property? We can roll your backflow testing into a regular maintenance schedule so nothing quietly lapses on you. For irrigation properties especially, it pairs well with keeping your reticulation and general plumbing running right through the year.
Every device gets installed and tested by a licensed plumber carrying the correct backflow endorsement. Pricing is quoted upfront — no nasty surprises when the invoice lands. Staying on top of compliance costs you a whole lot less than dealing with a failed audit. Or worse, a contamination event that puts your neighbours' water supply at risk along with yours.
We look after backflow compliance across Canning Vale, Thornlie, Willetton, Riverton, Southern River, Harrisdale, Gosnells and Huntingdale. Being local means we can slot your annual test in without a long wait. We also keep your records on file, so the next reminder comes from us — not from a Water Corporation letter that's been sitting in your mailbox for three weeks. Got a compliance notice you don't quite understand? Bring it in. Figuring out what those letters are actually asking for and sorting out your property's specific needs — honestly, that's half of what we do day to day.
Need a backflow device installed or your annual test done? Request a quote or call our licensed Canning Vale plumbers to stay compliant.
Frequently asked questions
Do I legally need a backflow prevention device in WA?
A lot of properties do. Water Corporation requires testable devices on a broad range of commercial, irrigation, fire, medical and higher-risk connections. Reticulation systems running on scheme water — that's a really common one too. If you're not sure, we can assess your particular property and tell you straight up whether it applies or not.
How often does a backflow device need testing?
Every year. That's the requirement in WA, and the test has to be done by a plumber with the correct backflow endorsement. Results get lodged with Water Corporation. What the test is really checking is whether the internal valves and seals still work — they degrade over time, so you can't just install it and forget about it.
What happens if my backflow testing is overdue?
Two things. You could get compliance action from Water Corporation, which nobody wants. And your protection against contamination — which is the whole point of the device — might not actually be functional anymore. We keep track of your due dates, come do the test, service the device if something's wrong, and lodge all the paperwork. You stay compliant without having to think about it.
My reticulation is on scheme water — does it need a device?
Quite possibly yes, and in a lot of cases it does. Reticulation connected to mains water — especially if there's fertiliser or chemical injection involved — is one of the most common reasons a backflow device gets required. There's reticulation all over Canning Vale and the surrounding suburbs, so we see this one a lot. We can inspect your setup and tell you whether you need one.