Auckland's dams are expected to dip under half full again, with dry skies forecast through to next week.
Dam levels are a long way from the historical average for this time of year of 76 per cent - and dropping near the mid-40s level that last year saw the city impose restrictions on residential and commercial users.
Level one restrictions - no hose without a trigger nozzle - are in place, but otherwise the city's water management company Watercare is relying on the goodwill of Aucklanders to keep use under 430 million litres a day.
Watercare's new chief executive, Jon Lamonte, said the forecast is for normal rainfall over the winter, but spring could be drier than usual, he said.
"The likelihood of harsher restrictions is low as I see it right now, but they're there if we need them," Lamonte said.
"Obviously, we're going to monitor the situation as we go through the winter and into the spring and really see what the rains bring us."
Last year, $224m was sought to boost the water supply.
The city is taking 175 million litres a day from the Waikato River, with an application for another 150 million litres in the works.
Waikato iwi objected to Auckland Council's bid to more than double the city's daily take from the river.
"We acknowledge the current low levels in Watercare's storage system, but don't support a short-term response that could cause long-term harm," Waikato-Tainui board chair Rukumoana Schaafhausen said last year.
In June last year, Environment Minister David Parker decided future sources of drinking water for Auckland were a matter of "national significance" and referred the application to take more water from the Waikato River to a Board of Inquiry.
Lamonte said extra water from the Waikato was "critical" to ensure Auckland's future water supply was adequate.
"The real buffer is going to be the Waikato. Bringing on the new water treatment plant in the Waikato, which will come up during this winter to give us an extra 50 million litres of water a day is going to be the safety net that helps us through it.
"Longer term... the Waikato means we're much less reliant on the dams themselves."
Auckland's population is expected to increase by about 400,000 over the next 10 to 20 years, meaning every water source needed to be tapped, Lamonte said.
Bores, aquifers and household water storage tanks could be used.
Smart meters are being rolled out to help people know how much water they use and detect leaks, Lamonte said.
Some facilities are using bore water rather than drinking water for irrigation and this approach could become more widespread.
Watercare had checked 4300km of pipes for leaks, saving 6.7m litres a day from going to waste, he said. Ongoing work to stop leaks will continue.
Aucklanders and Auckland Council were doing a great job of reducing their water use - and Lamonte hoped this would continue.
""We need to make sure everyone in Auckland carries on in exactly the same way as we're doing at the moment... and we will get through this together," he said.