Aucklanders kept water use down on what is usually a day of big demand

Aucklanders have managed to constrain their water use on a traditionally busy day.

The regional target is not to exceed 400 million litres a day - following the downpours that flushed a slug of silt into the Ardmore water treatment station, slashing its capacity to produce drinkable water.

Yesterday, the region used 406 million litres. Tuesday is typically one of the busiest days of the working week, says the regional water supplier, Watercare Services.

Auckland's water use was lower than for a typical Tuesday but still exceeded the target. Graph / Watercare

"Watercare generally finds that commercial customers gear up production mid-week, resulting in higher water consumption.

"So yesterday's result is a great sign the Save 20 message is really getting through.

"To put this into context, on Tuesday March 7, before the savings began, Aucklanders used 424 million litres."

The Save 20 message asks people to reduce their water use by 20 litres a day, which is two buckets of water.

Watercare is highlighting efforts to save water, including at Allied Concrete.

"They have five sites throughout Auckland and since the big rain event, have been making concrete using stormwater."

Allied Concrete sites in Auckland are using stormwater to make concrete. Photo / Supplied.

Blair Macfarlane, the company's northern regional manager, said: "Our Penrose site has significant stormwater storage and after the big dump of rain, we've been steadily working our way through the water, drastically reducing our reticulated-water use."

Today is World Water Day, an annual event designated by the United Nations.