Testing water quality

Melbourne has some of the world’s best drinking water, which we test regularly to ensure it meets strict water quality requirements — as well as checking aesthetics like colour, taste and smell. Know what we test, and view results of a typical analysis. 

O'Shannassy Reservoir
O'Shannassy Reservoir

Why we test water quality

High quality water is important to us. We work hard at making Melbourne’s water clean and healthy. To do this, we:

  • monitor the water quality within the catchments and distribution system through regular sampling and analysis
  • we monitor and research Melbourne’s rivers and creeks
  • we sample water at over 100 waterway monitoring sites
  • in summer, we test key recreational sites for E. coli and blue green algae
  • we regularly test water being transferred into businesses and homes, as a final check that it meets quality requirements.

Testing water quality helps us to fine-tune our water treatment processes, identify potential issues like algal blooms in advance, and decide where to transfer water, such as avoiding reservoirs with water quality issues.

 

Maroondah Reservoir water testing
Testing water at Maroondah Reservoir

Where we test

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

* storage reservoirs

* service reservoirs

* aqueducts

* transfer mains

* points of supply to our retail water customers.

 

What we test for

  • Clarity (turbidity)
  • Minerals and natural substances like iron and manganese

  • Colour

  • pH

  • Bacteria, such as E. coli

  • Chlorine and fluoride levels

  • Contaminants like fuel and pesticides.

 

 

mw01213-waterquality.jpg
Testing water quality

We follow strict standards

All the water we supply, no matter where it comes from, must meet strict water quality requirements.

We follow several 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.

We use independently-certified systems to manage water quality, including ISO 9001 and the HACCP (Hazard Analysis and Critical Control Point) system. Both are used in food and pharmaceutical industries worldwide.

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

 

But why does my water taste, smell or look different then?

Think your water looks a bit different today?

The colour, taste and smell of your water can actually change throughout the year. This is very normal and usually depends on the following factors:

  • source of water — your water can come from a number of reservoirs, each with natural differences in colour and mineral content
  • demand — people tend to use more water in summer, which causes it to travel faster through the pipes
  • temperature — temperature changes its taste (cooler water generally tastes better), and depends on the time of year.

 

Typical analysis of Melbourne's water

We test water quality from our major storage reservoirs once it has been through the primary treatment process. These results are used to provide a typical analysis of Melbourne's water quality, which is based on data from the previous five years. See the stats.

Results from January 2019

Please note:

  • all parameters are measured in milligrams per litre unless otherwise noted

  • values are rounded to the nearest decimal point.

​Parameter/ source Cardinia Greenvale Silvan Winneke Tarago​ Yan Yean​
pH (units)​ 7-7.6 7-7.9 6.8-7.8 7-7.4 7-7.3 6.8-7.4
Colour (Pt/Co)​ 0-5 0-10​ 3-13​ 0-2 0-5 0-5
Turbidity​ (NTU) 0.5-1.3 0.5-1.4 0.6-1.6

0-0.4

0-0.4 0-1
Specific conductance (uS/cm)​ 55-75 49-71 40-64 120-140 150-180 110-140
Iron 0.03-0.14 0.03-0.13 0.06-0.11 0-0.04 0-0.05 0-0.04
Manganese ​0.02-0.17 ​0-0.002 0-0.005 0-0.008 0-0.03 0-0.008
Fluoride​ 0.75-0.90 - 0.76-0.91 0.55-0.92 0.76-0.94 0.45-0.90
Aluminium - acid soluble​ 0.03-0.06 0.05-0.10 0.05-0.13 0.017-0.080 0-0.08 0.03-0.09
Arsenic​ <0.001​ <0.001​ <0.001​ 0-0.004 - 0-0.003
Boron​ 0-0.08 0-0.01 0-0.01 0-0.01 0-0.01 0-0.01
Bromide​ <0.05 <0.05 <0.05 <0.05 <0.05 <0.05
Cadmium​ - <0.0001 <0.0001 <0.0001 <0.0001 <0.0002
Calcium​ 4-6.5 3.7-5.2 3.0-5.0 5.6-7.8 8.0-10.0 5.6-7.8
Chromium < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001​
Copper​ 0.007-0.01 0-0.072 0.037-0.11 < 0.001-0.001 < 0.001-0.001 < 0.001-0.01
Haloacetic acids:​ ​ ​ ​ ​ ​ ​
- Chloroacetic acid​ (ug/l) < 3 < 3 < 3 < 3 < 3 < 3
- Dichloroacetic acid​ (ug/l) 3-9 3-7 5-21 < 1-17 5-10 < 1-17
- Trichloroacetic acid​ (ug/l) 18-20 3-10 28-48 7-30 5-12 ​7-30
Hardness​ 16-21 14-19 10-18 24-30 31-46 24-30
Lead​ <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
Magnesium​ 1.1-1.5 1.3-1.6 1.0-1.5 2.0-2.7 2.2-2.8 2.0-2.7
Mercury​ <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
Nickel​ <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
Nitrate​ 0.034-0.12 0.085-0.21 0.16-0.26 0.32-0.45 0.22-0.32 0.32-0.45
Potassium​ 0.54-0.76 0.68-0.75 0.62-0.68 1.2-1.5 1.9-2.4 1.2-1.5
Selenium​ <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
Silica as SIO2​ 3.9-5.7 2.3-7.2 5.9-7.0 3.4-5.2 4.3-6.0 3.4-5.2
Sodium​ 4-5 4.5-6 3.5-4.8 9.3-12 11-15 9.3-12
Total alkalinity as CaCO3​ 10-19 9-12 7-12 9-14 23-18 9-14
Total organic carbon​ 1.3-1.7 1.8-1.9 1.7-3.0 1.2-1.6 1.7-2.3 1.2-1.6
Total phosphorus​ 0.004-0.007 0.006-0.009 0.005-0.009 <0.004-0.015 0.01-0.019 <0.004-0.015
Total dissolved solids​ 35-42 31-41 32-38 73-84 92-95 73-84
Total trihalomethanes 0.0057-0.022 0.0056-0.02 0.0092-0.035 0.012-0.029 <0.001-0.015 0.012-0.029
Zinc​ 0.002-0.005 0.002 <0.001-0.004 <0.001-0.004 0.002 0.01

 

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    Last updated:
    11 June 2020