Waikato Regional Council is trialling a new monitoring system in an effort to crack down on breaches of its effluent management rules by the region's 4000 dairy farmers.
In 2009, 27% of more than 800 dairy farms randomly surveyed from the air were found to be breaking council rules. In the past year that dropped to 12%.
Council compliance manager Rob Dragten says the emphasis will shift this year from mostly using helicopters to monitor properties to ground-based work with farmers.
Mr Dragten says about 500 farmers will be targeted in areas where the soils pose a greater risk of allowing effluent to seep into waterways.
He says there has been a significant improvement in farmers' management of effluent in the past five or so years in which the council has been using helicopter monitoring.
Mr Dragten says the council has been working closely with the dairy industry to try to develop clear guidance on what constitutes a good effluent system.
He says the council is looking at changing its monitoring this year to give it more ability to advise and direct farmers to install systems that will be compliant all the time.
Meanwhile Dairy NZ, which represents the interests of dairy farmers, says farmers have to consider what impact the council's new monitoring system may have on their operations.
Effluent project manager Theresa Wilson says those on high risk soils should seek support if they feel the way they dispose of effluent needs to change.
She says Dairy NZ has just produced a new soils guide, which can help dairy farmers assess the risk of pollution.
Dr Wilson says the fact the regional council supports the Code of Practice for Effluent System Design should give farmers the clarity they have been asking for.