Melbourne will move to Stage Two water restrictions from the start of next month.

From September 1, householders with approved hose nozzles will be able to water their plants at all times, on all days.

Currently watering is only allowed early in the morning on alternate days.

Only approved drought-tolerant lawns can be watered under the relaxed restrictions.

The changed level of restrictions also means more flexibility in the use of sprinkler systems and car washing.

The Water Minister Tim Holding says householders have done a great job saving water in recent years, and deserve the change in restrictions.

"It's great news for households, for people with gardens, they want to see them thrive and grow," he said.

"This is the right time of the year now to be sending that message to people.

"It's terrific now that people will be able to wash their cars at home with the bucket and the high pressure hoses."