Whangarei District Council is putting formal water restrictions in place after earlier asking people to save water voluntarily.
The level two restrictions will come into force on at 8am on Wednesday, 26 February, and the council said level three restrictions may not be far behind.
For householders, level two restrictions ban sprinklers and irrigation systems.
For businesses the rules ban using sprinklers and irrigation systems on gardens, lawns and private fields, filling public fountains from water mains, taking construction water from water mains, watering sports fields except for those with approved watering plans.
Water services manager Andrew Venmore said dam, river and groundwater levels had fallen in the Whangarei District and not enough rain to replenish them was forecast in the coming months.
"Water restrictions will remain in place until water sources are sufficiently restored. Even when we get some rain it might not be enough to replenish the dam, so restrictions will be in place until we are confident we have enough water for next summer," he said.
"If we have normal rainfall this autumn, winter and spring, we will go back to normal quite quickly, but our concern is that if we have drier than usual seasons ahead, the water we have in the Whau Valley Dam right now is next year's water as well."
Venmore said people should try to reduce water use wherever possible.
"Whangarei residents have responded well to our calls over the past month to save water, dropping use across the district by 6.6 per cent since 12 February," he said.
"This tells us that people are taking the message on board, but with the dam level due to fall to 60 per cent next week, we need everyone to step their savings up a gear.
"Level two really just restricts a couple of water uses outdoors, but there are lots of ways people can save water indoors too. The bewaterwise.org.nz website has lots of useful tips and information about our water situation."