Water rates in Auckland are to be cheaper, but the long term cost of wastewater is still not known.
Local Government Minister Rodney Hide on Monday announced a new, cheaper flat rate for water as part of the super city reforms.
But a decision on a single rate for wastewater across the region will not be made for almost two years.
There are different charges in Auckland for wastewater depending on the location. Some, like those in Manukau, have a fixed yearly rate. Other areas, such as Central Auckland, are on a user-pays scheme.
Labour says it is concerned a more expensive user-pays system will be rolled out across Auckland.
It says that by delaying an overall decision on wastewater rates, Mr Hide is trying to avoid taking responsibility for a possible rise.
The new charge for water will be $1.30 per 1000 litres, compared with more than $2.30 in some parts of the region.
The biggest savings of 44% are for households in Orewa and Whangaparaoa, with 28% savings in Auckland City, 25% in Waitakere and 21% on the North Shore.
Manukau City presently has the region's lowest prices and will notice little difference.
The new Auckland Council will come into being on 1 November. It comprises eight existing councils.