Risk hierarchy of alternative water supplies from low risk (rainwater) through to high risk (sewage). Alternative water supplies are valuable sources of sustainable water. Water recycling conserves the high-quality water from our drinking water catchments for drinking and other personal uses, instead using alternative water supplies for non-drinking purposes. Water can be sourced from rainwater, stormwater, greywater, industrial water and sewage.

Water recycling uses water that is 'fit for purpose' – that is, the quality of water is safe for the intended use. Fit-for-purpose water can be safely used for non-drinking purposes such as irrigating public open space and flushing toilets.

Different types of alternative water supplies have different risks. Alternative water supplies need to be treated appropriately to ensure they are safe and fit for purpose.