Backflow Prevention and Drinking Water

The Gross Stuff That Could Be in Your Tap

Your water looks clear, so it must be clean, right? Not necessarily. In homes and businesses across Sydney, contaminated water is one plumbing fault away from flowing back through your kitchen tap. Most people have no idea it can happen.

It is called backflow. Water travels the wrong direction in the pipes, and instead of fresh mains water coming in, polluted water from garden hoses, irrigation systems, or chemical storage can siphon into your supply. It happens during pressure drops, main bursts, and unsafe plumbing setups. Backflow prevention devices and annual testing are legally required for many property types, and EKORP Plumbing (Lic 322223C) installs, tests, and certifies backflow devices across St George, Sutherland Shire, and the Georges River area.

What Is Backflow and How Does It Happen?

Backflow means water flowing backwards in your plumbing, from your property back into the public supply. When it reverses, it can carry bacteria, chemicals, or other pollutants along for the ride.

Two Types of Backflow

Backflow happens one of two ways:

• Back Pressure occurs when internal pressure in your system climbs above mains pressure. Pumps, boilers, commercial equipment, or gravity-fed tanks on a hill can all push potentially dirty water back into Sydney Water’s network.
• Back Siphonage happens when mains pressure suddenly drops, during a burst main, heavy hydrant use, or large water draw-offs nearby. The pressure difference creates a vacuum effect that sucks water backwards from your property.

Real-World Examples of Backflow Risks

• A garden hose sitting in a pool, tank, or chemical drum
• An irrigation system with no non-return valve fitted
• Commercial premises connected to cleaning agents or pesticides
• Car washes, dental surgeries, or factories with internal pressure systems
• Toilets or urinals in multi-storey buildings without correct zone separation

Without a backflow prevention device in place, there is nothing stopping that water from reversing into the same line that feeds your tap.

What Can Contaminate Your Drinking Water (And Who Is Most at Risk?)

Backflow is not just water going the wrong way. It is polluted water mixing into your clean supply.

Common Backflow Contaminants

• Pesticides and fertilisers from garden irrigation or rural properties
• Chlorine and pool chemicals from backyard pools or commercial spas
• Petrol and oils from driveways, workshops, or fuel storage
• Bacteria and sewage from cross-connections to toilets or stormwater
• Industrial waste from factories, laundromats, dental clinics, and labs
• Heavy metals and rust from corroded pipes under back pressure
• Cleaning agents from commercial kitchens, car washes, or medical practices

Properties Most at Risk

Certain properties carry higher risk and are legally responsible for preventing backflow under NSW regulations:

• Dental clinics and medical centres use sterilising chemicals and suction systems
• Cafes and commercial kitchens connect to grease traps and cleaning rigs
• Apartment blocks and strata complexes have large plumbing networks with cross-connection points
• Pools, spas, and gyms involve chlorine, backwash systems, and submersible hoses
• Schools and childcare centres have shared bathrooms and irrigation with a duty-of-care obligation
• Industrial workshops and car washes use oils, degreasers, and high-pressure systems

Even homes are not always off the hook. A rainwater tank plumbed into the house, a pool with automatic top-up, a pressure booster pump, or a sprinkler system all create obligations to protect the mains supply.

How Backflow Prevention Devices Work (And Which One You Need)

Backflow prevention devices stop contaminated water from reversing into the clean supply. They use a combination of valves, air gaps, and one-way systems. Not all devices offer the same level of protection. Requirements can vary by property and authority. We will help you confirm what applies before work begins.

Types of Backflow Prevention Devices

• Air Gap (AG) is a physical space between the outlet and a receiving tank or cistern. Common in rainwater tank setups. Simple and effective for low-hazard situations.
• Non-Return Valve (NRV) is a basic one-way valve that allows flow in one direction only. Suitable for domestic irrigation or pool systems at low hazard level.
• Double Check Valve Assembly (DCVA) uses two one-way valves in series with testable shutoff valves. It covers medium-hazard premises like commercial kitchens and small workshops. Annual testing and certification is required by law.
• Reduced Pressure Zone Device (RPZD) offers the highest level of protection, with relief valves, test cocks, and isolation valves. Mandatory at high-risk sites including medical facilities, chemical plants, and car washes. Yearly certification is compulsory.

Which Device Do You Need?

• Low risk (single homes with garden taps or rainwater tanks): Non-Return Valve or Air Gap
• Medium risk (cafes, hairdressers, small commercial): Double Check Valve Assembly
• High risk (hospitals, factories, chemical use): Reduced Pressure Zone Device

EKORP Plumbing assesses your property, its use, and your regulatory obligations to work out exactly which device applies, then installs it to Sydney Water and NSW Fair Trading standards.

Backflow Testing: What It Involves and Why It Is Legally Required

Fitting a backflow prevention device is only half the job. We will explain the workmanship warranty that applies to the job before work begins. That requirement is enforced by Sydney Water and NSW Fair Trading, not just recommended.

Why Annual Backflow Testing Matters

Backflow devices fail without making noise or tripping any alarm. Dirt, corrosion, debris, and mechanical fatigue can all knock a device out of action. Without annual testing, your water and your neighbours’ supply could be at risk without anyone knowing.

If your property is classified as medium or high risk in NSW, you must have a certified device installed, book annual testing, and submit test reports to Sydney Water. Skipping this can lead to compliance breaches, water supply restrictions, denied insurance claims in contamination cases, and legal liability for public health risks.

What EKORP Plumbing’s Backflow Test Includes

• Visual inspection of the device and its installation
• Pressure readings using certified test gauges
• Check of shutoff valves and relief valves where fitted
• Functional test to confirm water cannot reverse direction
• Submission of results to Sydney Water’s backflow register
• Service tag and compliance certificate issued on the spot

EKORP services residential, commercial, strata, medical, industrial, and hospitality properties across St George, Sutherland Shire, and the Georges River area. Emergency arrival times depend on location, traffic and plumber availability. We will give you an estimated arrival window when you call.

If You Are Not Sure, You Need to Be. Book a Backflow Check Today.

Backflow makes no noise and trips no alarm, but the consequences range from chemical contamination to public health breaches. If you do not know whether your property needs a backflow device, when it was last tested, or whether your current setup meets Sydney Water rules, it is time to get it sorted.

EKORP Plumbing (Lic 322223C) handles backflow prevention installation, annual testing and certification, and compliant reporting to Sydney Water for homes and businesses throughout the St George, Sutherland Shire, and Georges River areas. Give us a call on 02 8667 5354 and we will sort out the right solution for your property.