Water quality testing

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:

• Safe Drinking Water Act 2003 and Safe Drinking Water Regulations 2015 (Department of Health and Human Services)
• Australian Drinking Water Guidelines 2011 (National Health and Medical Research Council)
• our bulk water supply agreements with Melbourne’s retail water companies, which include water quality standards.

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

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