Water Treatment
Most of our water requires minimal treatment before being supplied to customers.
Water EcoScience conduct independent
checks of Melbourne's drinking water
The majority of Melbourne’s water comes from protected water catchments, where access is restricted to help ensure the highest quality water. (More on Water Catchments)
Purification of the water occurs naturally due to long retention/storage times in the major reservoir storage areas.
Minimal disinfection (by chlorination) is required to ensure our water is free from microorganisms that can cause disease.
Water is also fluoridated to help prevent tooth decay as required under the Fluoridation Act 1973.
A small amount of Melbourne’s water comes from the Sugarloaf Reservoir, which collects water from an open catchment. The catchment area is downstream from towns and farms, so this water undergoes full treatment at the Winneke Treatment Plant.
Minimal water treatment
The water treatment process involves disinfection, fluoridation and pH correction.
The addition of chemicals is continuously monitored and controlled to ensure the correct amounts are added to our water.
Chlorination is the preferred method of disinfection to ensure safe water is provided throughout the extensive distribution system in Melbourne.
Small amounts of chlorine are added to destroy any waterborne disease-causing microorganisms. The amount of chlorine added is equivalent to less than half a teacup in an average-size backyard swimming pool.
We also fluoridate the drinking water supply to help prevent tooth decay.
Chlorine and fluoride chemicals are slightly acidic, so lime is added to raise the pH level of the water back to neutral, limiting the possibility of corrosion to household pipes and fittings.
Full water treatment
Only about 20% of our water requires full treatment. Water from Sugarloaf Reservoir receives full treatment, as it is fed by water from the Yarra River, Maroondah Aqueduct, and the Sugarloaf Pipeline. The water is fully treated as it leaves the reservoir at the Winneke Water Treatment Plant.
Water from Yan Yean Reservoir is also fully treated as it has noticeable colour, high iron concentration and turbidity due to the nature of the soils and vegetation in the area and the shallowness of the reservoir. The Yan Yean Water Treatment Plant was completed in 1994 to overcome these water quality problems.
The Tarago Water Treatment Plant (completed in 2009) treats water from the Tarago Reservoir. Around 25% of the Tarago catchment is farmed land, including dairies and septic tanks. The treatment plant is complemented by an extensive catchment management plan.
Full treatment includes:
- Coagulation and clarification (to cause the colour and turbidity particles to settle out);
- Filtration (to remove most of the remaining suspended solids);
- Disinfection;
- Fluoridation; and
- pH correction.