Wellington's water ban has been lifted almost four weeks since sprinklers fell silent across the capital.

Regional authorities introduced a total ban on outdoor water use in mid-March after revealing there were only 20 days of water supply left.

They also started drawing water from the Hutt River and urged residents in Wellington, Porirua and the Hutt Valley to conserve stocks.

The shortage came after weeks without significant rain, as well as earthquake strengthening work which took one of two storage lakes at Te Marua out of action over summer.

The Greater Wellington Regional Council lifted the outdoor water ban at 9am today following rain over the weekend, but alternate day sprinkler restrictions remain in place in Wellington and Upper Hutt.

The council said recent rain had not been significant enough on its own, but public water savings and a promising forecast for next week meant the council was more positive about its ability to meet supply.

Water supply general manager Chris Laidlow said demand had dropped from more than 160 million litres a day to about 120-130 million litres a day, which meant the council did not have to use any water stored in reserve.

"In the event of continuing dry weather, we'll be able to supply water from rivers and the aquifer for four to five weeks before we'd have to look at using water from the storage lakes. Of course, this is dependent on demand staying at a reasonable level."

Regional council chairwoman Fran Wilde thanked residents for saving water and urged them to continue despite the ban being lifted.

"Worst case scenario, if we don't get the rain that we expect, we'll need to look at putting some level of restrictions back on, so I urge people to continue saving water.

"Just because the outdoor water ban has been lifted doesn't mean we can go for broke."

Ms Wilde said the drought had made most people realise they took their drinking water for granted, and saving water should not just be for times of drought.

"If lower water use in the region can delay the building of more water storage infrastructure, then there's a huge cost saving for the whole community."

- APNZ