Water bottling companies are paying an average 500 times less than ratepayers for each litre of water they're allowed to use.
A Herald investigation into water fees set by every regional council around the country found bottlers were charged an average $0.003 - or one third of a cent - per cubic metre of water.
Comparatively, in Auckland, Watercare charges $1.40 per cubic metre (1000 litres) for water piped to houses, while the rest of the country paid an average $1.60 per cubic metre.
• READ MORE: The war for water: A battle at boiling point
"Water companies are getting the same water but paying bugger all for it," said water campaigner Jen Branje from the Bung the Bore group.
"Why are ratepayers paying for something that corporates are getting almost for free? It's an unfair equation."
The new details come as the debate over water continues to simmer - last week one West Coast company was granted permission to pump 800 million litres a year to a tanker bound straight for China, flaming further outrage about the loss of a precious commodity offshore.
At the same time, other companies have been accused of "water banking" - holding the consents in the knowledge water is an ever-increasing commodity both here and overseas; or on-selling consents to others for profit.
The Herald requested consent details from each regional council following nationwide protests in March.
It asked how much water it had allocated to bottling companies, and what annual fees they paid.
The results showed in total, 23 billion litres per year had been allocated for bottling. Not all consents were active or fully in-use.
Water bottlers paid an average $200 per year in fees to council for duties such as consent monitoring or administration.
Because water is considered a public good in New Zealand, councils cannot charge for the water itself, although many of their fees were calculated from volume amounts.
Where are bottling companies taking water? Explore:
Note: Some figures were not provided in time for publication.
Councils' charging practices were highly inconsistent. While some, such as Auckland and Hawke's Bay, charged zero annual fees, others such as South Waikato - a district council - charged $1.05 per cubic metre under a special supply agreement.
Some councils either refused or were unable to provide exact details of their charges in time for publication.
The amount of water allocated also varied widely- some users were granted 7 million litres per year, while others such as Okuru Enterprises on the West Coast were granted upwards of 900 million litres annually.
Public information showed the average bottling company in New Zealand had a turnover of $1.5 million per year - excluding beverage giants Coca Cola Amatil and Frucor - which both have turnover of around $500 million a year.
Last year, 27 million litres of water were exported to countries including the United States, Germany, Japan and Australia. Water exports are valued at 80c per litre, with a total export value for 2016 of $21.5 million, according to Statistics New Zealand.
Both the Labour Party and the Greens said the new information showed there should be a charge for commercial users on water.
"Large users - irrigation, factory takes, and bottled water -should pay a royalty. That money should go back to local councils and Maoridom," said Labour's David Parker.
The Green Party's Catherine Delahunty said New Zealand didn't want to be known as the country who gave up their water for nothing.
"You can see why people are really upset. The public gets that it's a precious commodity, even if the Government doesn't."
However the New Zealand Beverage Council president Olly Munro said bottlers used less than 1 per cent of allocated water, while irrigation, for instance, used 50 per cent.
"It would be wrong to charge for the use of water for bottling while allowing other resource holders to continue to extract water without those same charges being applied," Munro said.
Branje said she believed it was time to take water management out of government hands.
"They've made such a hash of it. Water decline and mismanagement has been going on for 20 years now," she said.
Branje was part of a group that believed a new body - a Waterways Commission - should be set up to look after water interests.
It was an idea suggested by both Dame Anne Salmond, distinguished professor at Auckland University; and iwi, who say their rights are being ignored.
Environment Minister Dr Nick Smith said officials had been asked to look at the issue of water bottling in the wider context of work they were already doing on water allocation, and will report back by the end of the year.