What’s in Tap Water?

We often take it for granted that the water from our kitchen tap is safe and healthy to drink but is it really. While it is better to drink tap water then many other beverages available, tests show that tap water contains contaminants some of which are not healthy to drink.

The tap water quality varies from suburb to suburb and state to state depending upon the water source and treatment process. To get an idea of the water quality coming from your tap, go to “water quality in your suburb” section.

Water quality tests carried out have discovered up to 260 contaminants found in drinking water many of which are unregulated by the Australian Drinking Water Guidelines. The most common of these are industrial pollutants followed by agricultural and water treatment chemicals.

The two main chemicals added are chlorine and fluoride with smaller amounts of other chemicals such as aluminium sulfate added during the treatment process. All or some of these contaminants or added chemicals can be removed if required.


This chemical is added to disinfect or sanitise the water at the end of the treatment process killing bacteria, viruses and other micro-organisms. The by-product of this disinfection process is the production of THM’s or Trihalomethanes which are known carcinogens or cancer causing substances. For this reason many water supplies are now disinfected with chloramine.


Artificial fluoride is added to many drinking water supplies around the country based on the premis of reducing dental decay particularly in children. Although there are a great many studies showing the benefit of fluoride there appears to be just as many revealing adverse health effects.

Aluminium and Water Treatment Chemicals

Aluminum sulfate and other flocculant chemicals are used to remove suspended materials from the water supply. Small amounts or traces of these chemicals carry through the treatment process through to your tap.

Pesticides, Herbicides and Insecticides

These agricultural and industrial chemicals can wash into rivers, lakes and dams or leach into groundwater supplies sometimes several years after application. These chemicals are generally not removed by standard water treatment processes.


Some agricultural fertilizers once applied to the ground are very mobile leaching into ground water or running off farmland during rainfall into rivers, creeks and waterways. These fertilizers particularly nitrates find their way into town water supplies where only some is removed by the water treatment process.

Rust, Copper and Lead

All of these contaminants generally come from pipe work supplying water to your house or from pipe work within the house. This may be old galvanized pipes, copper pipe corrosion or lead leaching from old pipe joints. All of these things slowly contaminate the tap water endangering the health of those drinking the water.

Calcium and Magnesium

These naturally occurring minerals cause water hardness when their levels get too high in the water. Hard water requires more soap than soft water to obtain a lather or soapy bubbles. Water hardness can also cause scale to form on hot water appliances and air conditioners increasing corrosion and reducing efficiency. It can also alter the taste of the water.


Protozoan parasites contaminate drinking water supplies from time to time. This can be the case for treated town water supplies and rainwater tank storages. The two most common and well known types are giardia and cryptosporidium. These parasitic cysts have a hard shell protecting them from chlorine and other disinfectants making it very hard to remove from water supplies once they are contaminated. Both of these have contaminated major drinking water supply systems around the country causing mild to severe gastrointestinal symptoms in whose who ingest the parasites.


Bacteria levels and type are closely monitored in Australian Drinking Water supplies because they breed quickly and can cause large scale illness. Bacteria is generally killed by the treatment process and chlorine however if they are detected in water supply systems, the chlorine levels are immediately increased or consumers are asked to boil their water before drinking.

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