The Hidden Contaminants in Australian and Melbourne Water Supplies
While Australia’s tap water is generally considered safe by regulatory standards, that doesn’t mean it’s free from issues. By the time water reaches your home, it can carry a wide range of unwanted contaminants — from chlorine and heavy metals to microplastics, pesticides, and residual chemicals. These substances can affect the taste and odour of your water, compromise your health, and reduce the lifespan of your appliances.
Many of these contaminants aren’t visible to the eye, and most households have no way of knowing what they’re actually consuming. Factors such as aging infrastructure, urban runoff, chemical treatment processes, and even agricultural activity can all contribute to degraded water quality — even in major cities like Melbourne.
Contaminants can find their way into our water supply through various means:
Municipal Water Treatment and Disinfection Chemicals
To ensure tap water meets public health guidelines, water authorities use a range of disinfection processes — most commonly involving chemicals like chlorine and chloramine. These substances are effective at killing bacteria and viruses but can remain in the water by the time it reaches the home.
While disinfection is a necessary part of municipal water treatment, the residual presence of these chemicals can affect water taste, odour, and quality. In some cases, they may also react with organic matter in the water to form by-products such as trihalomethanes, which are tightly regulated but still present in trace amounts.
The balance between safety and chemical exposure varies depending on the source water and treatment practices, but it remains a contributing factor to the quality of tap water in homes across Melbourne and wider Australia
Ageing Pipes and Water Infrastructure
As water travels from treatment plants to homes, it passes through extensive networks of underground pipes — many of which are decades old. In areas with ageing infrastructure, corroded or deteriorating pipes can release materials such as rust, sediment, or even heavy metals like lead into the water supply. This is especially a concern in older suburbs or properties that still use outdated plumbing systems.
Even when water leaves the treatment facility in good condition, its quality can decline by the time it reaches the tap due to the condition of the delivery system. While Melbourne Water and local councils continue to upgrade infrastructure, ageing pipes remain a potential source of contamination.
Agricultural Run-Off into Catchments
Agricultural areas located near major catchments can contribute to water contamination when rainfall or irrigation causes fertilisers, pesticides, herbicides, and animal waste to wash into surrounding rivers and soil. These pollutants can make their way into protected catchments and reservoirs that supply drinking water to cities and towns across Victoria, including Melbourne. Although water treatment plants are designed to reduce much of this material, trace elements may still reach household taps, particularly during periods of heavy rainfall or increased farming activity.
Water Storage and Reservoir Contamination
Although Melbourne sources much of its water from protected catchments, storage reservoirs can still be exposed to environmental contamination. Factors such as sediment disturbance, organic debris, and wildlife activity can affect the water held in open reservoirs. In some regions, human access, agricultural runoff, or weather events like heavy rain and bushfires can also introduce foreign materials into these storage areas.
Even with robust treatment systems in place, the quality of stored water may vary depending on seasonal conditions, land use changes, and surrounding environmental factors. These fluctuations can influence the final water quality delivered to homes, making source protection and ongoing monitoring essential to maintaining safe supply standards.
Industrial Discharges into Waterways
Industrial activity can significantly impact the quality of our drinking water, particularly when waste products and by-products are discharged into nearby rivers, reservoirs, or groundwater systems. Even when treated, trace amounts of these industrial discharges can still find their way into municipal supplies.
These pollutants may enter the water system through improper disposal, stormwater run-off, or leaching from industrial sites, especially in areas located near manufacturing zones or older infrastructure. While water treatment facilities aim to neutralise these substances, some residual compounds can persist and travel through to residential taps.
Understanding the potential impact of industrial pollution is essential for those seeking a higher standard of water quality in their homes — and is one of the key reasons many households are turning to whole home water filtration systems as an added layer of protection.
Natural Events Like Bushfires and Heavy Rainfall
Environmental events such as bushfires, storms, and periods of intense rainfall can significantly impact the quality of source water. Ash, debris, and sediment from fire-affected areas can wash into catchments and reservoirs, altering the physical and chemical composition of the water. Likewise, heavy rain can stir up settled contaminants and increase the movement of pollutants from surrounding land into protected storage areas.
These events may temporarily overwhelm natural filtration zones or introduce spikes in organic material, which can affect both the efficiency of treatment processes and the final quality of water delivered to homes. While rare, these seasonal and climate-driven factors are increasingly relevant in Australia’s changing environmental landscape.
Leaching from Landfills and Waste Sites
Landfills and waste dumpsites can pose a long-term threat to surrounding soil and water quality. Over time, rainwater can seep through these sites and carry contaminants into groundwater or nearby waterways — a process known as leaching.
In some areas, this runoff may eventually enter the wider water supply, introducing a range of chemical residues and pollutants into catchments. While this is more common in poorly managed or older landfill sites, the risk still exists, especially where land use has changed over time or where water sources are located near former waste zones.
Although public treatment systems are designed to minimise these risks, filtration at the household level can offer added reassurance — particularly for those looking to reduce reliance on municipal safeguards alone.
What Contaminants Are Commonly Found in Treated Tap Water?
Now that we’ve explored how various sources can introduce impurities into our water supply — from catchment runoff to ageing infrastructure and treatment chemicals — it’s important to understand what those impurities actually are.
Even with thorough municipal treatment, certain substances can remain in the water or be introduced on the way to your taps. While many of these are present in low concentrations, regular exposure may impact water quality, health, and the condition of your home over time.
Below, we’ve outlined some of the most common contaminants found in Australian tap water — including those regularly detected in Melbourne — along with the potential side effects they may have.
Chlorine is commonly used in municipal water treatment across Australia, including Melbourne, to disinfect drinking water and eliminate harmful pathogens. While effective at sterilising the supply, chlorine doesn’t come without risks — particularly when it reacts with natural organic matter in the water.
This reaction forms a group of chemical compounds known as Disinfection By-Products (DBPs), including trihalomethanes (THMs) and haloacetic acids (HAAs). These by-products are tightly regulated but can still be present in trace amounts in treated tap water.
Long-term exposure to DBPs has been associated with a number of health concerns, such as:
Increased risk of bladder cancer
Potential impacts on liver and kidney function
Reproductive system complications
Central nervous system disruption
Higher likelihood of certain birth defects during pregnancy
Although chlorination is essential for preventing waterborne disease, awareness of DBPs highlights the importance of additional filtration — especially for families looking to reduce chemical exposure in their home’s water supply.
Heavy metals such as lead, copper, mercury, and arsenic can enter the water supply through ageing infrastructure, industrial activity, or natural deposits in soil and rock. In many Australian homes — particularly older properties — heavy metals may also leach from corroding pipes, plumbing fittings, or solder joints.
While regulated, these metals can still be present in trace amounts by the time water reaches the tap. Unlike organic contaminants, heavy metals do not break down in the body and may accumulate over time. Long-term exposure has been linked to a range of health concerns depending on the metal involved, including:
Developmental delays in children
Nervous system and kidney damage
Increased risk of certain cancers
Cardiovascular and reproductive issues
Filtration systems designed to reduce heavy metals are increasingly sought after by homeowners aiming to limit these risks and improve the safety of their household water supply.
Fluoride is added to most public water supplies across Australia, including Melbourne, as part of a government-run dental health program. While it’s intended to reduce tooth decay, the use of fluoride in drinking water remains highly controversial — both in Australia and internationally.
Many developed countries, including most of Europe, do not fluoridate their water, citing ethical concerns and the lack of strong evidence for benefits across the entire population. Critics argue that fluoride exposure through drinking water is difficult to control and does not account for varying levels of individual consumption or sensitivity.
Emerging studies have also raised concerns about potential long-term health impacts, including:
Dental and skeletal fluorosis from overexposure
Possible disruption to thyroid function
Associations between high fluoride exposure and reduced cognitive development in children
While fluoride is still approved for use in Australian tap water, more households are choosing to filter it out using specialised filtration systems that target fluoride at the point of entry or point of use.
Microplastics are tiny plastic particles less than 5 millimetres in size, often invisible to the naked eye. These particles can enter the water supply through environmental pollution, industrial discharge, and the breakdown of larger plastics in catchments and reservoirs. Microplastics are now being detected in tap water around the world, including in Australian cities like Melbourne.
Research has shown that microplastics can absorb and carry other harmful chemicals, potentially increasing their health impact. While the long-term effects of consuming microplastics are still being studied, early findings suggest potential risks to the digestive, reproductive, and endocrine systems. More recent studies have also identified the presence of nanoplastics — even smaller fragments — in bottled water, raising further concern about plastic exposure through drinking water.
Municipal treatment plants are not specifically designed to remove microplastics, which is why many households are turning to advanced filtration systems that can help reduce plastic particles at the point of entry or use.
Trace amounts of pharmaceuticals — including prescription drugs, over-the-counter medications, and hormone-based treatments — have been detected in drinking water sources around the world. These substances can enter the water system through human waste, improper disposal (such as flushing medications), and discharge from pharmaceutical manufacturing or agricultural operations.
While Australia’s water treatment facilities focus on eliminating harmful pathogens and chemicals, they are not specifically designed to filter out pharmaceutical residues. As a result, tiny concentrations of medications such as antibiotics, antidepressants, and hormonal compounds have been found in treated water in some studies.
Though these amounts are typically low, there is growing concern about the long-term effects of consistent, low-level exposure, particularly with regard to hormonal balance, antibiotic resistance, and environmental disruption. Whole home and advanced point-of-use filtration systems can help reduce the presence of these substances, offering an added layer of protection for households concerned about pharmaceutical contamination.
Nitrates are commonly introduced into the water supply through agricultural activity, particularly from the use of fertilisers, pesticides, and herbicides. When it rains or fields are irrigated, these chemicals can run off into surrounding waterways or seep into groundwater that eventually feeds into reservoirs.
Although treatment plants are designed to manage many contaminants, nitrates can be difficult to fully remove. Low levels may still remain in tap water, particularly in areas downstream from agricultural zones. Ongoing exposure is a concern for vulnerable groups, including infants and pregnant women, due to potential impacts on oxygen transport and long-term health.
Our Filtration Process
Tailored Systems Built Around Your Water and Your Needs
Water quality can vary drastically depending on where you live, how your water is sourced, and the condition of your local infrastructure. At PureFlow, we understand that no two homes — or households — are the same. That’s why we take a tailored approach to every system we install.
Whether your concerns involve chlorine, heavy metals, sediment, disinfection by-products, or bacteria, our team will recommend a solution that directly targets those issues. Our filtration range includes:
Whole home water filtration systems for comprehensive, property-wide protection
Reverse osmosis systems for highly purified drinking water at a single point of use
UV disinfection units for added protection where microbiological contamination may be present (such as tank or rural setups)
Each system is matched to your property after a free in-home water test and site inspection, where we assess your current water quality and installation requirements. From there, we provide a solution built around your health priorities, family size, and budget — with clear recommendations and no guesswork.
