By RNZ
Auckland's Watercare Services has repeated its plea to residents to shorten their showers to help save water.
Water supply dams in the Hūnua and Waitākere ranges are down to about 60 per cent of their capacity. The historic average for June is 84 per cent.
Watercare spokeswoman Roseline Klein said yesterday's heavy rain had helped and demand had fallen, but more rain was needed.
"The rain we've had this week is forecast to be the only significant rainfall event of the month of July.
"It is helping - but it is not making up for the deficit we've got from the start of the year," she said.
Niwa scientist Chris Brandolino said Auckland, Hamilton, Whangārei, Whitianga and Kaitaia all had the driest first half of the year, with some places receiving less than half the normal amount of rain.
The second half of the year is also expected to be drier than usual.
Klein said having quicker showers and fixing leaky toilets could make a big difference to water supplies.
"If everyone in Auckland was to reduce their shower time by one minute - that would save 18 million litres of water every day," she said.
Auckland Council-controlled Watercare, the region's water and wastewater company, has said it wants to fast-track moves to take more water from the Waikato River, to stave off the threat of a regional water shortage.
An existing resource consent allows up to 150,000 cu m of Waikato River water a day to be fed to the Auckland supply network.
In 2013, Watercare asked the Waikato Regional Council for permission to lift that to 200,000 cu m.
The Waikato River has been part of Auckland's water supply network since 2002. The river provides on average 37,000 cu m of water to the region each day.
Additional reporting - Herald staff reporter