"This is an issue of fairness. Right now, some Auckland businesses are paying more than they should while others are paying less than they should."
A choice of plans will be offered but big users will opt for a significantly higher fixed annual charge in order to pay less by volume.
However, those now paying more than a competitor on the other side of town will not see any compensating cut in their waste-water bill until after July next year.
This has disappointed Lion Nathan corporate affairs director Liz Read.
She said the company had planned and focused on sustainability and efficiency for a July 2013 introduction, as Watercare had originally flagged.
"So, those of us who are on the unfair side of the regime continue to bear the brunt while others geta free kick," Ms Read said.
However, the Employers and Manufacturers Association said it supported a three-year transition.
Watercare said it could not immediately give reductions for some while phasing in increases for others without upsetting its revenue stream in the short term.
This could have sparked price rises for everyone.
From July 1 next year, one-third of the new tariff will be charged at the new rate.
From July 1, 2015, two-thirds of it will be charged and from July 1, 2016, the full change kicks in.
