Ninety per cent of New Zealand's lakes and rivers will be clean enough to swim in by 2040.
That is the new target announced by the government this afternoon.
Environment Minister Dr Nick Smith said the plan "recognises that New Zealanders expect to be able to take a dip in their local river or lake without getting a nasty bug".
The new announcement means farmers will have to fence 56,000 kilometres by 2030 to stop stock going near the water and that is set to cost $367 million.
The level of what is deemed 'swimmable' is set to change. Dr Smith said if the water quality standards are met at least 80 percent of the time then that will be classed as safe.
"It will return our rivers and lakes to a standard not seen in 50 years while recognising that our frequent major rainfalls mean a 100 per cent standard is not realistic," he said.
At the moment 72 percent of our lakes and rivers are classified swimmable which means another 10,000km will need to be cleaned up by 2040.
Clean river campaigners said the government’s changes to freshwater policy to be announced today are yet another blow to New Zealand's declining rivers and lakes and a slap in the face to the public who have resoundingly called for a swimmable bottom line.
"After years of public calls for cleaner, swimmable rivers and lakes, the only thing Nick Smith and the government's new policy is going to do is lower swimming standards and make things worse," said Choose Clean Water NZ spokesperson Marnie Prickett.
"Nick Smith's new policy will allow more faecal contamination into rivers and lakes where New Zealanders are swimming – which means more poo in the water and increasing risk of infection."
"This is a slap in the face for all New Zealanders who have rationally called for safe, unpolluted rivers."