Why and how water is treated

Why and how water is treated

The way we treat water depends on its source. South Australia has a range of sources, more than 80 different water supply systems and we draw from the best treatment methods, based on what’s needed to maintain the highest quality of drinking water to everyone in the state.

Treating your water before it gets to you is important to make sure it looks, smells and tastes right and meets health standards. And there are many ways we do it.

We select the most effective and most appropriate way to filter and treat your water depending on its source. And each method ensures we reach our high standards.


Chlorine is used in the water treatment process to protect public health and ensure water is safe to drink, destroying bacteria and other pathogens that can be present in source water.


Like chlorine, chloramine destroys bacteria and other pathogens that can be present in source water and ensures tap water is clean and safe to drink. Because chloramine is better than chlorine at penetrating longer pipes it’s used in longer water distribution systems across the state.

Chloraminated water is a better tasting tap water. It regularly performs well in the annual best tasting South Australian tap water program, and is a favourite during our own blind taste tests. However, if you have aquatic pets, we would advise you to check out our information about caring for your aquarium as chloraminated water requires a different approach to chlorinated water.  If you’d like to know whether your drinking water is chloraminated, head to our handy search tool.


Our desalination plants use a technology called reverse osmosis which removes up to 99 per cent of the impurities and salt in the water. Once the impurities are removed, the water is treated to meet the Australian Drinking Water Guidelines, ensuring it is safe and ready to drink.

Saline concentrate is one of the by-products of the desalination process and at the Adelaide Desalination Plant at Lonsdale, this concentrate is put back into the ocean using a series of special diffusers. These sit about one kilometre off-shore and rapidly mix the concentrate with seawater to dilute it.


Fluoride is a trace mineral found naturally in water, soils and foods. It is added to South Australia’s metropolitan and major country drinking water supplies, as mandated by our state health authority, because it's proven to provide a significant public health benefit. Fluoride does not affect taste, look or the smell of your drinking water.

Other treatment options

Membrane filtration

We have strategically invested in membrane filtration plants, which represent the future of water treatment. This process passes water through smaller pore sizes on the membranes, which produce a better outcome. These provide more of a physical barrier against some pathogens, reducing the risk even further to the wider public.

Iron removal (IRP)

Many South Australian groundwater sources contain higher iron concentrations and other chemicals. The iron removal process removes these naturally-occurring elements from the water, and while the presence of iron in water does not pose any health risk and the water is safe to drink,  higher amounts can sometimes discolour drinking water and change its taste.

We are continually upgrading our iron removal plants to capture and reprocess backwash water. This reduces the amount of groundwater extracted and minimises environmental impact.

Magnetic ion exchange (MIEX)

Our Mount Pleasant and Middle River Water Filtration Plants were the first plants in the world to use Magnetic Ion Exchange (MIEX®) to treat the water.

This process – developed after years of research and teamwork by SA Water, industry leaders like Orica and research leaders like the CSIRO, removes the main cause of colour in the water: dissolved organic carbon. MIEX improves the taste and smell of drinking water, and also reduces the levels of chlorine needed.

Ultraviolet light (UV)

Ultraviolet light is used in some of our plants – exposure to appropriate doses of UV light destroys bacteria, viruses and protozoa, making them non harmful to humans. The required UV dose is dependent on certain water quality factors such as clarity, dissolved compounds and microorganisms present.

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  • 16/01/2020 01:17 PM - We are attending to an incident in Mile End with no interruption to the water supply. The safety of our crews and customers comes first, and we always aim to minimise inconvenience by restoring services as quickly as we can. Reference Number WO: 07265949.
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