Latest figures from the the country's main dairying region, Waikato, show the number of farms breaching dairy effluent management rules has dropped dramatically.
Waikato Regional Council has collated results from its annual aerial survey of more than 800 farms during the 2010- 2011 milking season.
Compliance manager Rob Dragten says the number of dairy farms significantly non-compliant with effluent rules was down from 27% in the previous season, to 12%.
Mr Dragten says 66% of the farms surveyed met all the council's effluent requirements compared with 51% in the 2009-2010 year.
The Dairy New Zealand organisation says the improvement in compliance levels in Waikato could be seen as a turning point in farmers' management of effluent, helped by the advice they're getting from it and regional councils.
It held workshops on effluent management, and developed effluent compliance checklists with regional councils across the country last season to give farmers greater guidance on what needs to be done on their farm.
Federated Farmers Waikato president James Houghton says it also reflect the huge investment farmers have been making to ensure their effluent systems are up to date and up to code.
More farms in Canterbury comply with rules
The rate of dairy farm effluent compliance has also continued to improve in the country's second biggest dairying region, Canterbury.
Preliminary figures from the regional council show 65% of Canterbury's 900 dairy farms were fully compliant with their effluent discharge conditions during the past year compared to 59% in the previous season.
There's been no change in the rate of significant non-compliance, which remains at 9%. That includes breaches such as effluent ponding, discharge of effluent too close to waterways and nitrogen overloading.
The regional council says that's still a big improvement on two years ago when 19% of dairy were farms found to be in serious breach of discharge conditions.