Greater Wellington Regional Council's chairman says installing residential water meters is "a must" to avoid a massive bill for building a new water source.
An economic case for the move has been tabled at a Wellington Water Committee and members have now directed the company to prepare a detailed business case.
GWRC has thrown its weight behind it, issuing a statement this morning saying it supported the decision to seek further refinement and costs for installing residential meters.
Chairman Daran Ponter said the region was blind to the scale of leak issues without metering.
Data for the 2019/2020 year suggests water losses across the region of up to 31 per cent.
Earlier this year Wellington Water discovered a 20,000-litre-a-day leak in Upper Hutt by installing just a handful of small meters in networks across the region's cities.
Ponter also said managing demand was fundamental to maintaining a sustainable supply.
The average household water use in the Wellington Metropolitan Region is more than 200 litres per person per day.
That is significantly higher than other major cities such as Auckland, at about 160 litres per person, and Melbourne, about 150 litres per person.
"By delivering vital information on personal consumption they will put control in the hands of consumers," Ponter said.
"They will drive changes to behaviour that will reduce consumption, take pressure off the region's ageing water infrastructure and avoid the need to invest millions in dams or other water sources."
Wellington Water Committee chairman David Bassett told his colleagues at a meeting yesterday they only needed to look at the executive summary of the economic case to realise the challenges the region was facing.
"Current demand for water in the Wellington Metropolitan Region is set to exceed supply in the near future and a new water source could be required between 2026 and 2030," the summary said.
Water metering is being looked at as a way to reduce demand to defer a $250 million investment in a new water source.
It could do so by 20 per cent, not so much by influencing consumer behaviour as through identifying leaks in supply pipes and fittings.
Porirua mayor Anita Baker said the region needed metering sooner rather than later.
She said there also needed to be a proactive push to educate people about water conservation.
"In Auckland they don't brush their teeth with the tap running, in Wellington they do. Have a bucket in the shower to save the water for your garden.
"And all these damn watering systems that run the minute the water restrictions come off, at 7pm or 9pm, frustrate the living daylights out of me. I'd like to see people fined."
South Wairarapa already has meters and mayor Alex Beijen urged his colleagues to install them too.
"Do it and do it now, it's a crucial part of being able to detect leaks. The sooner you do it, the sooner it becomes normalised."
But Upper Hutt mayor Wayne Guppy said building more bulk water storage needed to be the priority after 12 years of procrastination on the subject.
The committee has now directed Wellington Water to prepare a more detailed business case for residential meters.