Water quality testing

Melbourne has some of the world’s best drinking water. We regularly test it at multiple points throughout our water supply network, to verify it meets strict quality standards.

Did you know?

Your water’s colour, taste and smell can change throughout the year. This is very normal, and usually depends on factors like:

  • which reservoir your water is from – each naturally varies in colour and mineral content
  • demand – more water is used in summer, so it travels faster through the pipes
  • water temperature – cooler water generally tastes better.

Drinking water quality standards

No matter where it comes from, all the water we supply must meet strict water quality requirements. We are regularly audited under the Safe Drinking Water Act 2003, and report drinking water quality results and issues to the Department of Health each year.

The laws and guidelines we follow include:

Water quality testing verifies we meet these requirements. It also helps us fine-tune our water treatment processes, identify potential issues like algal blooms, and inform decisions on where to transfer water – for example, avoiding reservoirs experiencing water quality issues.

Water sampling and testing

Melbourne Water employee in laboratory testing water samples
Testing water samples at the Winneke Water Treatment Plant, located at Sugarloaf Reservoir.

We test water samples from over 160 sites within our water supply network each year – including our storage and service reservoirs, aqueducts and transfer mains. We also test water at points of supply to the retail water companies, as a final check that it meets requirements before being transferred into the network that supplies homes and businesses.

We test for a number of parameters, including:

  • 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
  • PFAS (per and polyfluoroalkyl substances).

Water quality data

The following data represents a typical analysis of Melbourne’s drinking water quality over a year. This is based on testing results at our major storage reservoirs, once water has been through the primary treatment process.

Tip: to fully view data tables on smartphones and tablets, place your finger on the table and scroll left or right.

Last updated: October 2024

Basic parameters
​Parameter Cardinia Greenvale Silvan   Sugarloaf Tarago​ Upper Yarra

Chlorine - free (mg/L)

0.52–1.70

0.64–1.40 0.80–1.80 0.58–1.20 0.18–1.20 0.11–1.30
Chlorine - total (mg/L) 0.57–1.90 0.78–1.50 0.98–2.00 0.70–1.50 0.22–1.40 0.23–1.70
Colour (Pt/Co) 2.00–6.00 2.00–8.00 2.00–10.00 2.00–6.00 2.00–4.00 2.00–10.00
E. coli (orgs/100mL) 0.00–0.00 0.00–0.00 0.00–0.00 0.00–0.00 0.00–0.00 0.00–0.00
Electrical conductivity (uS/cm) 51.00–110.00 56.00–84.00 40.00–80.00 79.00–150.00 110.00–190.00 45.00–82.00
Fluoride (mg/L) 0.23–0.94 0.73–0.86 0.05–0.90 0.05–0.98 0.69–0.91  
pH - field (pH units) 6.80–7.90 6.90–7.70 6.80–7.80 6.70–7.50 6.70–7.50

6.60–7.50

Total organic carbon (mg/L) 1.00–6.00 1.20–7.70 1.20–55.00 0.60–2.00

1.60–9.10

1.10–11.00
Turbidity - lab (NTU) 0.20–0.60 0.60–1.80 0.40–1.60 0.10–0.40 0.10–0.20 0.40–1.90
Metals
Parameter Cardinia Greenvale Silvan   Sugarloaf Tarago Upper Yarra
Aluminium (mg/L)

0.0020–0.0300

0.0600–0.1500 0.0400–0.0800 0.0100–0.0400 0.0100–0.0500 0.0300–0.0900
Aluminium - acid soluble (mg/L) 0.0050–0.0140

0.0120–0.0300

0.0220–0.0320

0.0120–0.0430 0.0100–0.0500 0.0120–0.0200
Arsenic (mg/L)

0.0010–0.0010

0.0010–0.0010 0.0010–0.0010 0.0010–0.0010 0.0010–0.0010 0.0010–0.0010
Boron - soluble (mg/L)

0.1000–0.1900

0.0200–0.0500 0.0200–0.0800 0.0200–0.0500 0.0500–0.0500 0.0500–0.0500
Bromide (mg/L)

0.0100–0.0500

0.0100–0.0500 0.0100–0.0500 0.0100–0.0100    
Cadmium (mg/L) 0.0002–0.0002 0.0002–0.0002 0.0002–0.0002 0.0002–0.0002 0.0002–0.0002 0.0002–0.0002
Chromium (mg/L) 0.0010–0.0010 0.0010–0.0010 0.0010–0.0010 0.0010–0.0010 0.0010–0.0010 0.0010–0.0010
Copper (mg/L)

0.0120–0.0900

0.0060–0.0250 0.0860–0.1600 0.0010–0.0010 0.0010–0.0010 0.0010–0.0020
Iron (mg/L)

0.0200–0.0900

0.0500–0.1400 0.0400–0.0900 0.0100–0.0300 0.0100–0.0200 0.0600–0.1000
Lead - total (mg/L)

0.0010–0.0010

0.0010–0.0010 0.0010–0.0010 0.0010–0.0010 0.0010–0.0010 0.0010–0.0010
Manganese (mg/L)

0.0010–0.0220

0.0010–0.0100 0.0020–0.0090 0.0020–0.0500

0.0010–0.0550

0.0020–0.0110
Manganese - soluble (mg/L)

0.0010–0.0030

0.0010–0.0010 0.0010–0.0040

0.0010–0.0050

0.0010–0.0050

 
Nickel (mg/L)

0.0010–0.0010

0.0010–0.0010

0.0010–0.0010

0.0010–0.0010

0.0010–0.0010

0.0010–0.0010

Zinc (mg/L)

0.0010–0.0060

0.0030–0.0120

0.0050–0.0080

0.0010–0.0020 0.0010–0.0020 0.0010–0.0010
Salinity indicators
Parameter Cardinia Greenvale Silvan   Sugarloaf Tarago Upper Yarra

Alkalinity (mg/L)

13.00–21.00 11.00–13.00 7.00–13.00 8.00–12.00 22.00–27.00 10.00–17.00

Calcium (mg/L)

5.10–8.10 2.60–5.10 1.70–7.20 4.40–7.60 7.50–11.00 1.50–2.30

Chloride (mg/L)

7.00–8.00 9.00–10.00 7.00–8.00 15.00–17.00 21.00–31.00 6.00–7.00

Hardness (mg/L)

16.00–25.00 11.00–21.00 10.00–27.00 16.00–28.00 27.00–38.00 9.00–14.00

Magnesium (mg/L)

0.90–1.20 1.00–2.00 1.10–2.20 1.30–2.10 1.90–2.70 1.20–1.90

Potassium (mg/L)

0.40–0.60 0.50–0.80 0.50–0.90 0.80–1.30 1.60–2.10 0.50–0.80

Sodium (mg/L)

4.40–5.20 4.50–6.90 3.50–5.80 6.70–10.00 10.00–13.00 4.20–6.00

Sulphate/sulfate (mg/L)

1.00–1.00 1.00–4.00 1.00–2.00 11.00–19.00 2.00–2.00 1.00–2.00
Disinfection byproducts
Parameter Cardinia Greenvale Silvan   Sugarloaf Tarago Upper Yarra

Bromodichloromethane (ug/L)

8.000–12.000 6.000–7.000 1.000–7.000 1.000–12.000 1.000–25.000 1.000–7.000

Bromoform (mg/L)

0.001–0.001 0.001–0.001 0.001–0.001 0.001–0.001 0.001–0.001 0.001–0.001

Chlorate (mg/L)

0.010–0.010 0.050–0.110 0.010–0.050 0.040–0.100   0.030–0.060

Chloroform (mg/L)

0.011–0.014 0.007–0.014 0.016–0.028 0.005–0.006 0.013–0.020 0.002–0.004

Dibromochloromethane (mg/L)

0.001–0.001 0.001–0.001 0.001–0.001 0.003–0.005 0.004–0.006 0.001–0.001

Dichloroacetic acid (mg/L)

0.005–0.014 0.005–0.005 0.007–0.025 0.005–0.005 0.005–0.013 0.005–0.010

Monochloroacetic acid (mg/L)

0.005–0.005 0.005–0.005 0.005–0.005 0.005–0.005 0.005–0.005 0.005–0.005

Trichloroacetic acid (mg/L)

0.005–0.015 0.005–0.005 0.006–0.021 0.005–0.005 0.005–0.012 0.005–0.008

Trihalomethanes (mg/L)

0.017–0.020

0.010–0.020

0.018–0.033

0.013–0.017

0.026–0.041

0.002–0.004

Nutrients
Parameter Cardinia Greenvale Silvan   Sugarloaf Tarago Upper Yarra

Ammonia (mg/L)

0.003–0.013 0.007–0.020 0.002–0.011 0.002–0.009 0.002–0.016 0.004–0.008

Nitrate (mg/L)

0.074–0.096 0.120–0.200 0.170–0.270 0.270–0.370 0.270–0.500 0.160–0.280

Nitrite (mg/L)

0.002–0.004 0.002–0.002 0.002–0.002 0.002–0.003 0.002–0.003 0.002–0.002

Nitrogen (TKN) (mg/L)

0.100–0.140 0.090–0.160 0.070–0.140 0.090–0.250 0.160–0.390 0.080–0.130

Nitrogen - total (mg/L)

0.200–0.210 0.220–0.290 0.240–0.370 0.390–0.570 0.520–0.750 0.280–0.390

Phosphate (mg/L as P)

0.003–0.005

0.004–0.006

0.003–0.005

0.003–0.006

0.003–0.009

0.003–0.006

Phosphorus - total (mg/L)

0.005–0.008 0.006–0.010 0.005–0.010 0.005–0.024 0.009–0.027 0.005–0.007
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