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 make sure it meets strict quality standards.

Did you know?

The colour, taste and smell of your water 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

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

The laws and guidelines we follow include:

Water quality testing ensures 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.

Each year we test water samples from over 160 sites within our water supply network – 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 onto 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.

Water quality data

The following data represents a typical analysis of Melbourne’s drinking water quality over the course of 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: January 2023

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

Chlorine - free (mg/L)

0.87–1.20 0.49–0.97 0.64–1.59 0.46–1.16 0.29–1.33 0.48–1.30
Chlorine - total (mg/L) 0.90–1.25 0.63–1.05 0.70–1.63 0.50–1.18 0.37–1.38 0.52–1.33
Colour
(Pt/Co)
2.00–6.00 2.00–6.00 4.00–12.00 2.00–5.00 2.00–6.00 4.00–14.00
E. coli (cfu/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) 67.00–105.00 64.00–109.00 50.00–103.00 98.00–136.00 135.00–170.00 48.00–91.00
Fluoride
(mg/L)
0.62–0.94 0.10–0.89 0.10–0.96 0.26–1.00 0.30–1.10  
pH - field
(pH units)
7.00–8.00 7.00–7.60 6.60–7.80 6.60–7.40 7.00–7.40

6.50–8.20

Total organic carbon (mg/L) 0.90–1.20 1.30–1.50 1.40–1.80 1.00–1.20

1.60–2.30

1.20–1.90
Turbidity - lab (NTU) 0.26–0.80 0.45–1.20 0.62–1.50 0.10–1.00 0.10–0.19 0.65–3.00
Metals
Parameter Cardinia Greenvale Silvan   Sugarloaf Tarago Upper Yarra
Aluminium (mg/L) 0.0060–0.0120 0.0180–0.0330 0.0240–0.0510 0.0130–0.1230 0.0110–0.1190 0.0200–0.0700
Aluminium - acid soluble (mg/L) 0.0040–0.0050 0.0120–0.0130 0.0160–0.0340 0.0130–0.0490 0.0110–0.0450 0.0120–0.0280
Arsenic (mg/L) 0.0003–0.0003 0.0003–0.0003 0.0003–0.0003 0.0003–0.0003 0.0003–0.0003 0.0003–0.0003
Boron - soluble (mg/L) 0.1700–0.2540 0.0200–0.1350 0.0200–0.0200 0.0200–0.0200    
Bromide (mg/L) 0.0250–0.0500 0.0250–0.0250 0.0250–0.0400 0.0250–0.0300    
Cadmium (mg/L) 0.0001–0.0001 0.0001–0.0001 0.0001–0.0001 0.0001–0.0001 0.0001–0.0001 0.0001–0.0001
Chromium (mg/L) 0.0001–0.0003 0.0002–0.0005 0.0002–0.0006 0.0001–0.0002 0.0001–0.0002 0.0001–0.0002
Copper (mg/L) 0.0136–0.0190 0.0038–0.0148 0.0447–0.1154 0.0003–0.0004 0.0001–0.0002 0.0002–0.0003
Iron (mg/L) 0.0114–0.0326 0.0261–0.0745 0.0453–0.1106 0.0005–0.0415 0.0012–0.0094  
Lead - total (mg/L) 0.0002–0.0003 0.0001–0.0002 0.0001–0.0003 0.0001–0.0001 0.0001–0.0001 0.0001–0.0001
Manganese (mg/L) 0.0005–0.0054 0.0004–0.0088 0.0019–0.0138 0.0016–0.0126

0.0001–0.0410

 
Manganese - soluble (mg/L) 0.0001–0.0022 0.0001–0.0007 0.0001–0.0036 0.0003–0.0100 0.0001–0.0148  
Nickel (mg/L)

0.0001–0.0001

0.0004–0.0007

0.0003–0.0005

0.0003–0.0005

0.0001–0.0002

0.0005–0.0006

Zinc (mg/L)

0.0006–0.0039

0.0028–0.0043

0.0025–0.0074

0.00004–0.00010 0.0003–0.0004 0.0003–0.0008
Salinity indicators
Parameter Cardinia Greenvale Silvan   Sugarloaf Tarago Upper Yarra
Alkalinity as CaCO3 (mg/L) 19.00–24.00 13.00–15.00 7.00–14.00 11.00–13.00 23.00–30.00 10.00–13.00
Calcium (mg/L) 6.12–7.90 4.00–4.43 2.10–4.70 4.40–7.77 8.39–11.40 1.60–2.04
Chloride (mg/L) 6.00–8.00 9.00–10.00 7.00–9.00 15.00–19.00 23.00–25.00 7.00–8.00
Hardness (mg/L) 2.00–22.00 5.00–18.00 5.00–18.00 7.00–29.00 6.00–39.00 6.00–13.00
Langelier Index (unitless) 1.90–2.20 2.20–2.70 2.20–3.70 2.30–2.50 1.60–2.10 2.90–3.60
Magnesium (mg/L) 0.37–0.93 1.33–1.78 1.22–1.92 1.59–2.46 1.41–2.86 1.48–1.82
Potassium (mg/L) 0.26–0.61 0.58–0.71 0.50–0.77 1.08–1.33 1.21–2.02 0.55–0.72
Sodium (mg/L) 3.80–6.96 5.00–6.60 2.70–4.50 7.60–11.30 10.10–12.50 4.26–8.72
Sulphate/sulfate (mg/L) 0.60–1.80 0.60–1.80 0.60–1.80 6.90–12.90 0.90–2.40 0.60–3.00
Total dissolved solids (mg/L)

37.00–58.00

35.00–60.00

28.00–54.00

54.00–75.00

75.00–94.00

26.00–50.00

Disinfection byproducts
Parameter Cardinia Greenvale Silvan   Sugarloaf Tarago Upper Yarra
Chloroacetic acid (ug/L) 3.00–3.00 3.00–3.00 3.00–3.00 3.00–3.00 3.00–3.00 3.00–3.00
Dichloroacetic acid (ug/L) 2.00–6.00 4.00–6.00 14.00–21.00 4.00–6.00 7.00–9.00 6.00–11.00
Trichloroacetic acid (ug/L) 2.00–4.00 3.00–4.00 8.00–11.00 3.00–4.00 6.00–9.00 1.00–1.00
Trihalomethanes (ug/L)

9.00–17.00

12.00–16.00

19.00–28.00

19.00–27.00

37.00–46.00

4.00–22.00

Nutrients
Parameter Cardinia Greenvale Silvan   Sugarloaf Tarago Upper Yarra
Ammonia (mg/L) 0.005–0.048 0.006–0.014 0.005–0.026 0.005–0.024 0.005–0.015 0.005–0.009
Nitrate (mg/L) 0.012–0.058 0.099–0.152 0.197–0.307 0.076–0.494 0.340–0.602 0.205–0.358
Nitrite (mg/L) 0.003–0.004 0.003–0.003 0.003–0.003 0.003–0.007 0.003–0.004 0.003–0.003
Nitrogen (TKN) (mg/L) 0.060–0.170 0.120–0.280 0.050–0.230 0.080–0.370 0.180–0.380 0.070–0.320
Nitrogen (total) (mg/L) 0.080–0.220 0.270–0.440 0.250–0.510 0.380–0.780 0.580–0.930 0.280–0.630
Phosphorus (total) (mg/L)

0.005–0.012

0.005–0.012

0.005–0.009

0.005–0.022

0.013–0.018

0.005–0.010

Last updated: