Mkhize, on behalf of the inter-ministerial task team on water, told the media in Parliament on Tuesday that his decision was gazetted as at 10am this morning.
Government previously reclassified the water crisis as a national disaster on 8 February.
However, this was different to a declaration. Government can now access special funds through Treasury reserved for national disasters.
The process to calculate how much will be released has begun and the figure will be announced at a later date, Mkhize said.
“As the Minister responsible for disaster management, I have recognised that special circumstances exist, and have decided to declare the drought as a national state of disaster in terms of Section 27 of the Disaster Management Act,” he said.
Mkhize called on all citizens to continue to save water and change behaviour, as South Africa is a water-scarce country.