The Te Kowhai farmer – Edward Smith – has been convicted and fined $35,625 in the Hamilton District Court.
Contamination was found during a routine inspection as part of its compliance monitoring programme in March 2017, the Waikato Regional Council said in a statement.
A waste holding pond was overflowing, the drainage pipe was blocked and dairy waste had flowed into the environment.
Judge Melanie Harland said the inadequacies of the effluent infrastructure on Smith’s farm were “barely adequate”.
The management of the system was “woefully inadequate”, Harland said.
The Waikato Regional Council’s investigation manager Patrick Lynch said the waste infrastructure and management of it needed to be a high priority.
“The judge’s comments reinforce the message that both the council and the industry itself have been promoting for years,” Lynch said. “It is very disappointing to find that some farms continue to operate with inadequate storage.
“This fine is yet another clear message from the court that people who do not take their environmental responsibilities seriously will be heavily penalised.”