Turning on the tap and being greeted with a dirty, foul-smelling stream of water is a worrying sight. If you are a Sydney local or visiting the city, you would expect the water you drink to be clean and safe. If residents find that the water they are drinking has suddenly become contaminated, they may be experiencing a backflow emergency and should contact a professional plumber immediately.
At Backflow Testing, our licensed technicians see the devastating effects of cross connections on a daily basis. Contaminated water can put your family, employees, and even the entire community at risk of serious illness.
This article will discuss everything you need to know about backflow contamination, including telltale signs and what to do if you encounter any.
What is Backflow Contamination?
The contamination of potable water supply is associated with backflow conditions which may be a result of changes in pressure, allowing contaminated water to enter the supply.
Rather than the liquid going safely away from your home, the dangerous liquid is sucked back into the pipes of your drinking water. This results in a serious health hazard. The siphon effect can occur when there is a drop or rise in pressure, with back-siphonage being a drop in pressure and back-pressure being an increase.
Back-siphonage is the result of a drop in pressure within the water supply, which can cause the liquid to be drawn back into the system. You should read our entire guide on what backflow is and why it is actually dangerous in the first place to learn more details.
7 Warning Signs of Backflow Contamination in Your Water
Recognizing the signs of backflow contamination can help avoid serious health problems down the road. Here are some signs that something is wrong with your water. If you see any of these signs, stop using your water right away.
1. Discoloured or Murky Water
Potable water is clear water. If your tap water suddenly turns brown, yellow, green, or pink, that means there is probably a cross-connection in your plumbing.
- Brown or rust-coloured: This could indicate soil, rust or sediment getting into your pipes.
- Yellow or green: Algae, agricultural run-off or chemicals could be contaminants in your water.
- Cloudy or milky: This is often caused by air getting into the system, but could also be caused by chemical contaminants.
2. Foul or Unusual Odours
Your water should never have an odour. If there has been a backflow, it will smell of the substances in to which it has been exposed. If your tap water smells of rotten eggs (sulphur) sewage, harsh chemicals or strongly of chlorine, you must not drink it. A smell of sewage is an indication that your drinking water has been contaminated with waste water.
3. A Strange or Bad Taste
Note: Never intentionally taste water you suspect is contaminated.
If you take a sip of it before noticing the other signs and it tastes metallic, bitter, salty, or soapy, you should spit it out right away. Those are all signs that industrial chemicals, heavy metals, or cleaning fluids may have made their way into your water supply.
4. Sudden Drops in Water Pressure
Backflow is caused due to pressure changes. A sudden drop of the water pressure in your Sydney property can cause back-siphonage. This happens when you have a drop of the main water pressure that is significant in magnitude and occurs across your house or business. This is what leads to the suction of contaminated water back into your water supply.
5. Visible Sediment or Particles
Finding specks of sediment or unusual flecks in your glass of water is an indication that your pipes are contaminated. Backflow can lead to the ingestion of undesirable stagnant water and dirt from irrigation pipes, fire sprinkler systems or large industrial water tanks.
6. Sputtering or Spitting Taps
Air pockets in your plumbing system can cause your taps to sputter, spit, and hiss when you turn them on. Air pockets can form in your plumbing system even when you have routine plumbing repairs done. These air pockets can also be formed when the water in your system backs up and pockets of air are created. If you notice a smell or discoloration along with the sputtering, then you may have a backflow problem in your system.
7. Slow Drainage Across the Property
While a clogged sink is typically a localized issue, multiple slow drains can indicate a main line sewer backup. If the city sewer is backing up, without appropriate backflow prevention, the sewage can contaminate the system within your building.
What Causes Backflow in Sydney Properties?
Knowing why backflow occurs is crucial in determining the causes affecting your property. The main reason for backflow is the difference in pressure, and it is split into two categories:
Back-Siphonage (Negative Pressure)
The first type is called siphonage and occurs when the pressure in the main line is lower than the pressure of your water supply. In this case, the system acts like a straw.
Common causes in Sydney include:
- Water Mains Breaks: If there is a broken pipe in a suburbs such as Parramatta or the Inner West it causes a drop in pressure in the local streets.
- Fire Hydrants: Firefighters often open hydrants to let out large quantities of water which causes a drop in pressure for others.
- Water Usage: Very high usage on a hot summer day can sometimes cause a drop in water pressure.
Back-Pressure (Positive Pressure)
Back-pressure is a situation where the pressure of water inside your home or business is greater than that of the main water supply in your area. This means that the water is attempting to flow backwards, which may cause water that is dirty to be pushed into the clean water. Common causes include:
- Commercial Pumps: The high-pressure pumps used in factories or high-rise buildings in the Sydney CBD.
- Boilers and Heating Systems: The increase in temperature in boilers or heating systems causes the pressure in the system to rise.
- Elevated Tanks: Using a high overhead tank to allow gravity to feed the supply into the system may result in overpowered pressure in the main.
The Immediate Health and Safety Risks
Backflow contamination is a serious health issue. Based on the source of a cross-connection, water may be contaminated with pathogenic organisms and toxins.
What Could Be in the Water?
- Biological Hazards: E. coli, salmonella, giardia, and raw sewage.
- Chemical Hazards: Pesticides, fertilizers, heavy metals, and industrial cleaning solvents.
- Physical Hazards: Dirt, rust, glass shards, and pipe degradation materials.
Drinking this water can cause serious gastrointestinal problems, skin rashes, heavy metal poisoning and even deadly infections. For cafes, restaurants, and medical institutions, using such water means termination of their work due to the violation of NSW Health guidelines.
What to Do Immediately If You Suspect Backflow
Time is of the essence. Here is what you should do if your water supply is contaminated for any reason. First and foremost,
- Stop Using the Water: Do not drink it, do not cook with it, and do not wash your hands in it or shower with it.
- Do Not Boil the Water: Boiling the water will kill the bacteria but it will also concentrate the toxic chemicals and heavy metals in the water. Since you have no idea what’s in the water, you shouldn’t boil it.
- Turn Off the Main Water Valve: Locate your water meter, which is typically found at the edge of your property and turn the isolation valve to the right to cut off the supply to prevent the contaminated water from spreading.
- Isolate Individual Hazards: Turn off valves to any suspected sources of contamination, such as the garden or the pool, if they can be isolated.
- Call a Licensed Backflow Plumber: You will need an accredited plumber to test the cross connection. You can contact our team at Backflow Testing Sydney to conduct emergency inspections and tests.
- Notify Your Neighbours and Sydney Water: In the event that your neighbours have suspected that a street water main is the cause of the back-siphon, you should let them know. It is also recommended that you notify Sydney Water’s emergency service of such occurrences.
Residential vs Commercial Backflow Risks
The sources of contamination may vary depending on the type of property. We deal with both residential houses in the Sutherland Shire and high-risk industrial facilities in Blacktown. Here is the comparison:
| Property Type | Common Cross-Connection Hazards | Hazard Rating (Sydney Water) |
| Residential Homes | Garden hoses submerged in pools/buckets, irrigation systems, rainwater tanks. | Low to Medium |
| Restaurants & Cafes | Coffee machines, commercial dishwashers, grease traps. | Medium to High |
| Industrial / Factories | Chemical mixing tanks, high-pressure washers, cooling towers. | High |
| Medical & Dental | Sterilisation equipment, chemical dispensers, dialysis machines. | High |
| Strata & High-Rises | Fire sprinkler systems, booster pumps, shared HVAC boilers. | Medium to High |
Medium and High hazard properties are legally required to have testable backflow prevention devices installed at the boundary.
Sydney Water Regulations & Your Responsibilities
It is the responsibility of all property owners in the state of New South Wales to ensure that pollution does not occur in the water supply.
According to the Australian Standards (AS/NZS 3500.1) and Sydney Water requirements, the properties with Medium and High hazard rating must install an appropriate backflow prevention containment device.
The Annual Testing Requirement
Installation of a valve is not a “fit and forget” exercise. The springs and seals inside them wear out over time. As such, Sydney Water has mandated by law that testable devices such as Reduced Pressure Zone (RPZ) valves and Double Check Valves be tested every twelve months.
Failure to submit the reports may result in large amounts of penalties, disconnection of the water supply, or even complete termination of the water service.
Our in-house licensed technicians will perform the required testing of your equipment, perform any necessary maintenance or repairs, and complete the required paperwork for you and submit directly to Sydney Water on your behalf to ensure you are always compliant.
How to Prevent Future Backflow Issues
The best way to deal with contamination is to prevent it from even occurring. There are several ways you can do that on your property.
Install the Right Prevention Devices
Valves are different depending on the threat they need to stop.
- For hazards that could make someone sick or worse, you need RPZ Valves (Reduced Pressure Zone). These send any water that might have been infected down a relief valve so that it can’t get into your clean water.
- Lower level threats like nuisance or bad-tasting water, you need Double Check Valves. They stop water that could be bad from going backwords to your clean lines. If you have an outside tap, you need a Hose Connection Vacuum Breaker. It stops the water being used by your hose from flowing back into your home.
Maintain an Air Gap
An air gap is the most basic and reliable type of backflow prevention. An air gap is the space between the water outlet (the opening where the water flows out of the aerator or spout) and the flood level rim (the top edge of an overflowing receptacle such as a sink). Never connect a garden hose to a tap and leave the other end of the hose in a bucket of soapy water or in a swimming pool.
Book Regular Maintenance
Commercial premises have to stick to their yearly check-up schedule. But if you are a homeowner in Chatswood or Ryde or anywhere else, it is a good idea to have your plumbing system serviced every few years or so, particularly if you have elaborate irrigation for your garden or a tank connected to it.
Need Immediate Help with Backflow Contamination?
Ignoring signs of water contamination puts all of your employees, workers, and residents on your property at risk. Whether you’re noticing discoloured water in your residential home or a faulty RPZ valve at your commercial location, it’s time to act now.
Our team of Backflow Testing Sydney experts are qualified to identify potential cross-connections, install high-quality prevention devices, and ensure the safety of the water supply in your building. We also offer the required annual tests and inspections for Sydney Water.
Secure your water supply now, call our professional team who can inspect your site, perform your annual test, and even respond to emergencies throughout Sydney.
Frequently Asked Questions (FAQs)
What is a cross-connection in plumbing?
A cross-connection can be an actual or potential direct physical connection between a potable water supply and a source of contamination such as a swimming pool with a garden hose lying in it or a chemical feed tank, or irrigation system.
How do I know if my RPZ valve has failed?
An RPZ valve is meant to vent water from the line either due to a pressure surge from an unexpected source or a pressure drop in the main supply. So if your RPZ valve is leaking or dumping significant amounts of water from the relief port, the good news is, it is likely doing its job correctly by preventing the back-flow of water, but the internal seals will most likely need to be professionally serviced.
Can I test my backflow prevention device myself?
No. According to the plumbing and drainage legislation of New South Wales, only a licensed plumber who holds a particular backflow prevention accreditation can legally test, repair, and certify the devices. Moreover, plumbers need to use special testing equipment that has to be calibrated every year to remain accurate.
Who is responsible if backflow contaminates the street’s water?
A property owner is responsible for ensuring that cross connections on your property do not cause a backflow that pollutes the municipal supply. You can be prosecuted by Sydney Water and charged with enormous sums of money if cross connections on your property cause Sydney Water to have to take action to decontaminate the supply.
Why does my water smell like rotten eggs?
A rotten egg or sulphur smell is an indication that there may be gases such as hydrogen sulphide in the water. Sewage or wastewater can sometimes backflow into the clean water supply due to a cross-connection. If this happens, do not drink the water and contact an emergency plumber to come and locate the cross-connection.
Does boiling contaminated water make it safe?
Not necessarily because boiling water kills bacteria and other disease-causing organisms, but it does not eliminate heavy metals, pesticides, and other inorganic toxins. Indeed, boiling water evaporates the clean water and concentrates the heavy metals and toxins resulting in more dangerous water to drink.