Understanding Backflow Prevention and Why It Matters in Perth

If you’ve ever noticed a strange taste or colour in your tap water, you know how unsettling it can be. One of the major culprits for water contamination in homes and businesses is something called “backflow.” In Perth, where we all rely on clean, safe water, understanding backflow prevention isn’t just smart – it’s essential for protecting your family, your property, and the wider community.

What Is Backflow, Exactly?

Backflow happens when water flows in the opposite direction to what’s intended. Instead of clean water moving from the mains into your plumbing, contaminated water from your property can flow back into the mains supply. This can happen if there’s a sudden drop in water pressure (like when a pipe bursts or there’s a big demand on the main supply), or if something in your system causes a reversal of flow.

The result? Fertilisers, chemicals, or even just dirty water from hoses, pools, or industrial processes can find their way into the public drinking water supply.

Why Is Backflow a Risk in Perth?

Perth’s mix of older and newer suburbs, along with our love for reticulation systems, pools, and home renovations, means there are plenty of opportunities for backflow hazards. Backflow risks are especially high in places with cross-connections—spots where drinking water meets non-potable water sources, like irrigation systems, fire hoses, or commercial processes. Even a garden hose left in a pool or fish pond can become a backflow risk.

What Are the Legal Requirements for Backflow Prevention in WA?

Western Australia takes backflow prevention seriously, and so should you. Here’s what you need to know:

• Mandatory Backflow Devices:By law, any property that poses a risk of backflow—commercial, industrial, and even some residential—must have an appropriate backflow prevention device installed. This requirement comes from both the Plumbing Code of Australia and local Water Corporation by-laws
• Annual Testing: Backflow prevention devices must be tested every year by a licensed plumber certified in backflow prevention. The results are then reported to your water supplier (in Perth, that’s usually the Water Corporation).
• Responsibility:; Property owners are responsible for making sure backflow devices are installed, tested, and maintained.

If you’re not sure whether your property needs a device, or if your existing device is up to date, it’s worth getting a professional inspection.

How Regular Inspections Protect Your Health

Backflow events can be silent and invisible—you often won’t know anything’s wrong until contamination has already happened. That’s why regular inspections and annual testing aren’t just about ticking a box for the council. They’re about peace of mind and public safety. A certified plumber will check for:

• Cross-connections or plumbing changes that could create new risks
• Proper function of existing backflow devices
• Signs of wear or tampering

Catching problems early keeps your water safe and prevents costly repairs down the line.

What Should Perth Homeowners and Businesses Do Next

If you’re a homeowner, check if your property has a backflow prevention device (common in homes with irrigation, pools, or rainwater tanks connected to mains water). If you run a business—especially a café, car wash, medical centre, or industrial site—you almost certainly need a device and a maintenance plan.
Book a licensed plumber with backflow certification for an inspection and yearly test. Keep records of all testing and device servicing, as you may need to show them to the Water Corporation or local council.

The Bottom Line

Backflow prevention isn’t just a box to tick—it’s a critical part of keeping Perth’s water supply safe for everyone. If you’re not sure about your risk or your legal obligations, give Ember Plumbing and Gas a call. We’ll help you get compliant and keep your water clean, year-round.