Desalination can handle drinking water but 90% of water usage is usually for irrigation. It is not cost effective to do that with desalination. As for Australi

Desalination can handle drinking water but 90% of water usage is usually for irrigation. It is not cost effective to do that with desalination. As for Australia's 6 or 7 built/planned desalination plants: they are for backup and supplemental purposes only. They can't supply more than about 10% of the largest Australian cities' typical water usage. They would provide emergency water in a catastrophic drought and in low rainfall years can lessen the burden but they are not a replacement for good water catchment management.