Your home’s plumbing system delivers clean, safe water to every tap, shower, and appliance. When flow reverses, contaminated water can enter your drinking supply, posing serious health risks. A backflow prevention device is essential to protect your family.
Understanding Backflow in Your Plumbing System
Backflow occurs when water flows in the wrong direction within your plumbing system. Instead of clean water moving toward your taps, contaminated water from outside sources, or even within your property, can reverse course and enter your main water supply. This reversal introduces dangerous contaminants into your drinking water, including:
- Pesticides and fertilisers from irrigation systems
- Bacteria and parasites from soil
- Chemicals from lawn treatments
- Human waste from sewage systems
- Soap and detergents from appliances
What Causes Backflow?
Back Siphonage
This happens when there’s a sudden drop in water pressure in your supply line. A vacuum effect pulls water backward through the system. Common causes include nearby burst pipes or firefighters using fire hydrants, which dramatically reduce pressure in the local water network.
Back Pressure
This occurs when the pressure in a contaminated water source exceeds the pressure in your clean water supply. Water naturally flows from high-pressure areas to low-pressure areas, forcing polluted water into your potable system. Irrigation systems and boilers are typical culprits, as they can generate higher pressure than your main water line.
How Backflow Prevention Devices Work
A backflow prevention device creates a physical barrier in your plumbing that ensures water flows in only one direction, into your home. These devices are installed at critical points where clean and contaminated water systems might connect, preventing any reversal of flow. The device monitors water pressure on both sides of the valve. If it detects conditions that could cause backflow, it automatically closes to protect your water supply.
Types of Backflow Prevention Devices
Reduced Pressure Zone (RPZ) Valves
These offer the highest level of protection and are commonly required for commercial properties or homes with high-risk cross-connections. They feature two independent check valves with a pressure-monitored chamber between them.
Double Check Valves
These use two check valves in series to prevent backflow. They’re suitable for lower-risk applications but don’t provide the same level of protection as RPZ valves.
Atmospheric Vacuum Breakers
These simple devices are often used on outdoor hose connections and irrigation systems. They allow air into the line when pressure drops, preventing back siphonage.
Do You Need a Backflow Prevention Device?
If your property has any of these features, you likely need a backflow preventer:
- Irrigation or sprinkler systems
- Swimming pools or spas
- Fire suppression systems
- Boilers or heating systems
- Commercial equipment connected to water lines
- Wells or secondary water sources
In Western Australia, properties with irrigation systems are required by law to have backflow prevention devices installed. This protects not just your household but the entire neighbourhood’s water supply from contamination.
Installation and Testing Requirements
Backflow prevention devices must be installed by licensed plumbers who understand local plumbing codes and proper placement. The device is typically located near your water meter or main shutoff valve to provide maximum protection. Once installed, these devices require annual testing to ensure they’re functioning correctly. A certified backflow tester will check the valves, pressure settings, and overall operation. This is a legal requirement in most areas to protect public health.
Our team at Aus Star Plumbing & Gas can assess your plumbing system, recommend the right backflow prevention device, and handle installation to meet all local regulations. Protect your property and your family’s health. Contact us today for professional installation and ongoing maintenance.