Supplier's plea: Save water now

Lower Nihotupu Dam in the Waitakeres. Photo / Brett Phibbs

Auckland's water stores are falling despite yesterday's downpour, prompting the region's bulk water supplier to ask residents to cut water use by 4 per cent.

Watercare Services says it does not know how dry this winter will be, and wants to make sure it does not have to impose compulsory restrictions next summer.

Dams in the Hunua and Waitakere Ranges were 58.7 per cent full yesterday - 10 percentage points less than normal for this time of year.

That was still well above the 37.5 per cent levels on April 27, 1994, the last year Aucklanders faced compulsory water restrictions.

Since 1994 the Waikato River water treatment plant and pipeline have been built to supply up to 20 per cent of Auckland's water.

And, unlike 1994, rainfall is expected to be back to normal by the end of winter, after an El Nino weather pattern weakens.

But after a record-dry January to March, the soils around the water storage dams are parched.

MetService figures for Auckland show 33.4mm of rain have fallen so far this month, less than half the average of 78mm. This year 89.6mm has fallen - less than a third of the average of 298mm.

The region's water supply lakes, which began the summer 100 per cent full, are expected to fall to 50 per cent by the end of next month.

Watercare Services networks manager Mark Bourne said if they did not refill by September, compulsory restrictions were likely.

A 4 per cent drop in water use would bring consumption back to normal levels.

Aucklanders - who are efficient water users compared with other cities - cut consumption 1.7 per cent last week, after Watercare began running advertisements asking people to use less water. Mr Bourne said there was a danger people would relax this week because it was raining.

"We have these 'green droughts', where it will continue to rain, but the amount of rain will be much less than usual."

Watercare's records show rainfall in the past three months has been the lowest in nearly 100 years of records in the western water supply catchments and the third lowest in nearly 50 years in the southern catchments.

CUTTING DOWN
* Fill the kettle with only as much water as you need.
* Half-fill the sink to wash vegetables rather than washing them under a running tap.
* Take a quick shower rather than having a bath.
* Replace your old shower head with a water-efficient shower head and save up to 9 litres of water a minute.
* Turn off the tap while brushing your teeth and save up to four litres of water each time.
* Wait until you have a full load before turning on the washing machine.
* Use a bucket of soapy water rather than a hose to wash your car and wash it on the lawn so that the grass benefits from the water. A hose can use 30 litres of water a minute.
* Hand-water the garden in the early morning or evening to minimise evaporation.
* Check around the house for leaks.