Prior to the mid 1990s, Melbourne Zoo used more than 1,000 kilolitres of potable water per day, averaging 570,000 kilolitres per year. The average daily water use steadily declined to 640 kilolitres of potable water per day in 2005, 540 kilolitres per day in 2006 and 380 kilolitres per day in 2007. Recent reductions can be attributed to continued efficient water use, compliance with water restrictions and the commissioning of the Recycled Water Plant.

Class A recycled water from the Western Treatment Plant is used at Werribee Open Range Zoo for landscape irrigation. The use of recycled water further reduces Zoos Victoria’s reliance on drinking water.

In a world first for a Hippopotamus exhibit, a natural filtration process has been employed at Werribee Open Range Zoo to treat water in the Hippopotamus pools. This water is pumped through a 5,000 square metre wetland system, treating it to a high standard.