Water quality testing

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:

• Safe Drinking Water Act 2003 and Safe Drinking Water Regulations 2015 (Department of Health)
• 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 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

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