Spokesman Mark Champion says Watercare wants to create a level playing field across the city, as it has done with domestic customers. Watercare is considering various proposals.
One offers the same fixed rate and volumetric charge for everyone. Two others offer higher fixed annual charges for higher-volume users, and varying degrees of decreasing volumetric charges.
Another suggests a flat volumetric charge but increasing annual charges based on usage.
Depending on which proposal you look at, high users could be in for fixed fees of up to $75,000 a year. Volumetric charges range from $2.74 to $4.36 a kilolitre.
At present, the Tanners are paying $1.40 a kilolitre for their water.
Some business owners fear they will be charged 10 times as much in the future.
Janine Bunsdon, of the North Harbour Business Association, says she can understand why commercial water charging needs attention. "There needs to be consistency across Auckland."
But she says some small businesses would be charged more than residential customers, even under the cheapest rates proposed.
"We have four people in our office.
"We would use less water than the average domestic property but our charge per kilolitre is substantially higher."
Business owners have been concerned about the water charges for a while, says Auckland Chamber of Commerce chief executive Michael Barnett. "For no other reason than being a business, businesses have to pay more. It seems inequitable."
Some of the options proposed show a lack of innovation, he says. "We're hoping when we see the final tariff regime it will better reflect the sort of mix business has in input and usage."
The chamber has told Auckland Council it is not happy a council-owned entity is imposing a charge on business owners that could make them reconsider whether they stay in Auckland or move elsewhere, Barnett says.
In the end, the consumer will pay. Robert Bonnici, who owns Car Fe in Takapuna, says the proposed changes will push car-wash prices up. Since the Super City was established, his water bills have increased nearly 200 per cent to $800 a quarter, he says. "This is just another piece of profit we have to give to the council."
Service-station car washes will be even more adversely affected than his business because car-wash machines use water less efficiently. "It would have an impact on us but it won't close us down," says Bonnici.
But some business owners complain even the present system of charging is not fair and gives businesses on a cheaper rate an unfair advantage. Brett Morman, of Harmony Homes in West Auckland, has to pay a set fee each year for wastewater based on land value, no matter what his businesses uses.
Last year, he paid more than $4000 in wastewater costs, even though his business used just $128 worth of water. Morman says his company is subsidising others around the city.
Nearby, Jim Turnbull of Jetpatcher paid $545 for water in - and $6493 for water out - last year. Comparable businesses on the North Shore are paying half that, he says, making it impossible to compete.
Volumetric charging will also benefit businesses that use large quantities of water but do not discharge it as wastewater.
Companies such as beverage giant Lion have thrown their weight behind a flat, volumetric charge with stepped annual charges related to usage.
Lion spokeswoman Liz Read says it is important to apportion costs to those who impose costs on the system. Read will not say how much the company's water bills will drop under the plan.
But in its submission, Lion says its wastewater charges have risen, despite a cut in its wastewater discharge.
Lion has asked for the changes to be implemented immediately, rather than allowing a period for adjustment. Any transition period would only prolong existing inequities across Auckland, Read says.
Watercare's Mark Champion knows whatever decision it makes, there will be some big winners and some big losers. "We're trying to create fairness." A decision is due early next month.
In East Tamaki, the Tanners are resigned to waiting to find out how much their next water bill will be. "All we can do is make a submission," says Karen Tanner. "We're just waiting to see now."
