Bay of Plenty Regional Council says Maori landowners are playing their part in helping improve the water quality of Lake Rotorua.
Results of official tests show the trophiclevel index - measuring four factors to determine water quality - has improved to the point that it is now below the target for the region's water and land plan.
Council natural resource manager Warwick Murray says this year the clarity of water in the lake has been excellent.
One reason might be that some waterways feeding into the lake are being treated to remove excess phosphate.
Long term, the quality of water in the lake is in the hands of local farmers which includes a substantial number of Maori trusts, says Mr Murray.
The council has a positive relationship with Maori landowners, who tend to take a long-term view of the need to improve the health of the lake, he says.