Water quality

Melbourne has some of the highest quality drinking water in the world, which we test regularly to ensure it meets strict water quality requirements. We look at the health-related aspects of water quality, as well as aesthetic factors like colour, taste and smell.

Learn about the standards we meet, why water quality can vary, and how we monitor it.

Standards for water quality

All the water we supply, regardless of its source, must meet strict water quality requirements. We follow a number of laws and guidelines:

  • Safe Drinking Water Act 2003 and Safe Drinking Water Regulations 2005, set and administered by the Department of Health and Human Services

  • Australian Drinking Water Guidelines 2011, developed by the National Health and Medical Research Council

  • water quality standards set in our bulk water supply agreements with the retail water companies

To make sure our water meets these requirements, we use our own Independently certified systems for managing quality. These include ISO 9001 and the HACCP (Hazard Analysis and Critical Control Point) system, both used in organisations worldwide – including food and pharmaceutical industries.

Our systems are audited regularly under the Safe Drinking Water Act 2003, and we report all drinking water quality issues to the Department of Health each year:

Why water quality varies

The colour, taste and smell of your water can vary at different times of the year. This is very normal and usually depends on where your water comes from, demand for water in your area and water temperature.

Source of water

Each reservoir stores water with natural differences in colour and mineral content. Your water may come from different reservoirs at different times of the year, depending on how water is moved around the supply system to manage demand.

High demand

People tend to use more water in summer, which causes it to travel faster through the pipes.


The taste of water changes depending on its temperature, which in turn is affected by the time of year. Cooler water generally tastes better.

Monitoring water quality

We regularly test water being transferred to homes and businesses, as a final check that our water quality meets requirements.

Each year we test about 50,000 samples from over 160 sites, including:

  • storage reservoirs

  • service reservoirs

  • aqueducts

  • transfer mains

  • points of supply to our retail water customers

The retail water companies monitor water quality at selected taps.

We test each sample for:

  • clarity (turbidity)

  • mineral content and other natural substances, like iron and manganese

  • colour

  • pH

  • bacteria, such as E. coli

  • chlorine and fluoride levels

We also make sure there are no contaminants like fuel and pesticides.

As well as verifying water quality, monitoring allows us to fine-tune our water treatment processes so that we add chemicals in the precise amounts needed relative to the quality of the untreated water.

It also helps us identify potential issues in advance, such as algal blooms, and decide where to transfer water – for example, avoiding taking water from a reservoir with water quality issues.

To find out more about water quality in your specific area, contact your retail water company:


Last updated:
20 September 2017