An Opotiki farm company has been fined $37,000 for discharging effluent into a roadside drain last July.
Riverlock Farms and farm manager Geoffrey Brown were sentenced in the Rotorua District Court on Thursday.
Brown was also ordered to undertake a dairy farm effluent management course within 12 months.
Bay of Plenty Regional Council says the effluent entered a drain which flows into the Waioeka River.
The court was told that there had been two previous prosecutions for effluent discharges from the farm.
Judge Jeff Smith said the penalty would have been higher had the company not made significant improvements to the farm's effluent system, including installing three new storage ponds.